&EPA
United States Office of Soi'O Waste and
Environmental Protection Emergency Response
Agency Washington DC 20*60
EPA 530-SW-86-031
OSWER Policy Directive No 9-72 002
October 1986'
Technical Guidance
Document:
Construction Quality
Assurance for
Hazardous Waste Land
Disposal Facilities
PB87-132825
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TECHNICAL REPORT DATA
/Please ftad Instructions on the went btfon computin
t. MEPORT NO.
EPA/530-SW-86-031
4. TiTLi AND SUBTITLE TECHNICAL GUIDANCE DOCUMENT:
Construction Quality Assurance for Hazardous Waste
Land Disposal Facilities
3. RECIPIENT'S ACCESSION NO.
October 1936
ING ORGANIZATION CODE
7, AUTH0FMS)
Col sen M. Northiem and Robert S. Truesdale
8. PERFORMING ORGANIZATION BEPORT NO
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Research Triangle Institute
P.O. Box 12194
Research Triangle Park, NC 27709
10. PSOGRAM ELEMENT NO.
VI. CONT«ACT/G«ANT NO.
68-02-3992, Task 032
12. SPONSORING AGENCY NAME AND ADDRESS
Hazardous Waste Engineering Research Laboratory
Office of Research and Development
26 W. St. Clair Street
Cincinnati, OH 45268
13. TYPf 0f= REPORT AND PERIOD COV6R6O
EPA-530/00
S. SUPPLEM!NTAHY NOTES
OSWER Policy Directive No. 9472.003
• Construction quality .assurance (CQA) as applied in this document uses scientific
and engineering principles and practices to ensure that a hazardous waste land disposa
facility is constructed to meet or exceed all design criteria, plans, and specifi-
cations. The document covers CQA for hazardous waste landfills, surface impoundments,
and wastepiles. The major components of these facilities that are addressed include:
foundations, dikes, low-hydraulic-conductivity soil liners, flexible membrane liners,
leachate collection systems and final cover systems. The document is intended to
complement the Minimum Technology Guidance being issued by EPA's Office of Solid
Waste,
At a minimum, the CQA plan should include five elements. These are: 1) res-
ponsibility and authority, 2) CQA personnel qualifications, 3} inspection activities,
4) sampling strategies, and 5) documentation.
This document describes these elements in detail and presents information on
those activities pertaining to each of the elements that are necessary to ensure that
the facility is constructed to meet or exceed the specified design. It is intended
for the use of organizations involved in permitting, designing, and constructing
hazardous waste land disposal facilities.
KEY WORDS AND DOCUMENT ANALYSIS
OISCRIPTORS
b.lD6NTIFIEHS/OP£N £ND£O TERMS C. COSATI Field/Group
S. DISTRIBUTION STATEMENT
Release to Public
EC* F«M» 2220-1 (R..- 4.77)
19. SECURITY CLASS fTIUS Rtpart)
Unclassified
21. NO. OF PAGES
1D1
20. S6CURITY CLA
Unclassified
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OSWER Report No. EPA/530-SW-86-031
OSWER Policy Directive No. 9472.003
October 1986
TECHNICAL GUIDANCE DOCUMENT
Construction Quality Assurance
For Hazardous Waste
Land Disposal Facilities
68-02-3992
Task 032
Project Officer
Jonathan G. Herrmann
Land Pollution Control Division
Hazardous Waste Engineering Research Laboratory
Cincinnati, Ohio 45268
In cooperation with
Office of Solid Waste and Emergency Response
U.S. Environmental Protection Agency
Washington, DC 20460
HAZARDOUS WASTE ENGINEERING RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
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DISCLAIMER
The Information in this document has been funded wholly or in part by
the United States Environmental Protection Agency under Contract No. 68-02-
3992, Task 032, to Research Triangle Institute. It has been subject to the
Agency's peer and administrative review, and it has been approved for
publication as an EPA document. Mention of trade names or commercial
products does not constitute endorsement or recommendation for use.
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FOREWORD
Today's rapidly developing and changing technologies and industrial
products and practices frequently carry with them the increased generation
of solid and hazardous wastes. These materials, if improperly dealt with,
can threaten both public health and the environment. Abandoned waste sites
and accidental releases of toxic and hazardous substances to the environment
also have important environmental and public health implications. The
Hazardous Waste Engineering Research Laboratory assists in providing an
authoritative and defensible engineering basis for assessing and solving
these problems. Its products support the policies, programs, and regula-
tions of the U.S. Environmental Protection Agency; the permitting and other
responsibilities of State and local governments; and the needs of both
large and small businesses in handling their wastes responsibly and economi-
cally.
This Technical Guidance Document (TGD), prepared in cooperation with
the Office of Solid Waste and Emergency Response, presents the elements of
a construction quality assurance plan that should be addressed during the
permit application procedure for a hazardous waste land disposal facility
(i.e., landfill, surface impoundment, wastepile). These elements are:
(1) areas of responsibility and lines of authority in executing the construc-
tion quality assurance plan; (2) requisite qualifications of construction
quality assurance personnel; (3) types of inspections (observations and
tests) to be performed as part of construction quality assurance activities;
(4) sampling strategies (including sampling frequency, size, and location;
acceptance and rejection criteria; and corrective action implementation);
and (5) documentation of construction quality assurance activities. The
TGD discusses assuring construction quality for several facility components.
These components are foundations, dikes, low-permeability soil liners,
flexible membrane liners, leachate collection systems, and final cover
systems.
This document is intended for use by organizations involved in permit-
ting, designing, and constructing hazardous waste land disposal facilities.
Thomas R. Hauser
Director
Hazardous Waste Engineering
Research Laboratory
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PREFACE
Subtitle C of the Resource Conservation and Recovery Act (RCRA) requires
the U.S. Environmental Protection Agency (EPA) to establish a Federal
hazardous waste management program. This program must ensure that hazardous
wastes are handled safely from generation until final disposition. EPA
issued a series of hazardous waste regulations under Subtitle C of RCRA
that are published in Title 40 Code of Federal Regulations (CFR) Parts 260
through 265 and Parts 122 through 124.
Parts 264 and 265 of 40 CFR contain standards applicable to owners/
operators of all facilities that treat, store, or dispose of hazardous
wastes. Wastes are identified or listed as hazardous under 40 CFR Part 261.
Part 264 standards are implemented through permits issued by authorized
States or EPA according to 40 CFR Part 122 and Part 124 regulations. Land
treatment, storage, and disposal (LTSD) regulations in 40 CFR Part 264
issued on July 26, 1982, and July 15, 1985, establish performance standards
for hazardous waste landfills, surface impoundments, land treatment units,
and wastepiles. Part 265 standards impose minimum technology requirements
on the owners/operators of certain landfills and surface impoundments.
EPA is developing three types of documents to assist preparers and
reviewers of permit applications for hazardous waste land disposal facili-
ties. These are RCRA Technical Guidance Documents (TGDs), Permit Guidance
Manuals, and Technical Resource Documents (TRDs). Although emphasis is
given to hazardous waste facilities, the information presented in these
documents may be used for designing, constructing, and operating nonhazardous
waste LTSD facilities as well.
The RCRA TGDs present design, construction, and operating specifications
or evaluation techniques that generally comply with or demonstrate compliance
with the Design and Operating Requirements and the Closure and Post-Closure
Requirements of Part 264. The Permit Guidance Manuals are being developed
to describe the permit application information the Agency seeks and to
provide guidance to applicants and permit writers in addressing information
requirements. These manuals will include a discussion of each step in the
permitting process and a description of each set of specifications that
must be considered for inclusion in the permit.
The TGDs and Permit Guidance Manuals present guidance, not regulations.
The do not supersede the regulations promulgated under RCRA and published
in the CFR. Instead, they provide recommendations, interpretations, sugges-
tions, and references to additional information that may be used to help
interpret the requirements of the regulations. The recommendation of
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methods, procedures, techniques, or specifications in these manuals and
documents is not intended to suggest that other alternatives might not
satisfy regulatory requirements.
The TRDs present summaries of state-of-the-art technologies and evalua-
tion techniques determined by the Agency to constitute good engineering
designs, practices, and procedures. They support the RCRA TGDs and Permit
Guidance Manuals in certain areas by describing current technologies and
methods for designing hazardous waste facilities or for evaluating the
performance of a facility design. Whereas the RCRA TGDs and Permit Guidance
Manuals are directly related to the regulations, the information in the
TRDs covers a broader perspective and should not be used to interpret the
requirements of the regulations.
This document is a Technical Guidance Document. It was prepared by
the Hazardous Waste Engineering Research Laboratory of the Office of Research
and Development at the request of and in cooperation with the Office of
Solid Waste and Emergency Response. The TGD was first issued as a draft
for public comment under the title, "Construction Quality Assurance for
Hazardous Waste Land Disposal Facilities" (EPA/530-SW-85-021) dated October
1985. All comments received on the draft TGD have been carefully considered
and, if appropriate, changes were made in this final document to address
the public's concerns. With issuance of this document, all previous drafts
of the TGD are obsolete and should be discarded.
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ABSTRACT
The U.S. Environmental Protection Agency's (EPA's) construction quality
assurance (CQA) program for hazardous waste land disposal facilities is a
two-part program established to ensure that a completed hazardous waste
land disposal facility has been constructed to meet or exceed all design
criteria, plans, and specifications. The first part of this program will
present regulations that specify the use of construction quality assurance
at hazardous waste land disposal facilities and is being developed by the
Office of Solid Waste and Emergency Response. The second part of this
program, addressed by this Technical Guidance Document (TGD), presents the
elements of a site-specific CQA plan. This TGD covers CQA for hazardous
waste landfills, surface impoundments, and wastepiles. The major components
of these facilities that are addressed include foundations, dikes, low-permea-
bility soil liners, flexible membrane liners, leachate collection systems,
ind final cover systems.
The CQA plan is a site-specific document that should be submitted
during the permitting process to satisfy EPA's CQA program. At a minimum,
the CQA plan should include five elements, which are briefly summarized
btlow:
Responsibility and Authority—The responsibility and author-
ity of organizations and key personnel (by title) involved
in permitting, designing, and constructing the hazardous
waste land disposal facility should be described in the CQA
plan.
CQA Personnel Qualifications—The qualifications of the CQA
officer and supporting CQA inspection personnel should be
presented in the CQA plan in terms of the training and exper-
ience necessary to fulfill their identified responsibilities.
Inspection Activities—The observations and tests that will
be used to ensure that the construction or installation
meets or exceeds all design criteria, plans, and specifica-
tions for each hazardous waste land disposal facility component
should be described in the CQA plan.
Sampling Strategies—The sampling activities, sample size,
methods for determining sample locations, frequency of
sampling, acceptance and rejection criteria, and methods for
ensuring that corrective measures are implemented as addressed
in the design criteria, plans, and specifications should be
presented in the CQA plan.
vi
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Documentation—Reporting requirements for CQA activities
should be described in detail in the CQA plan. This should
include such items as daily summary reports, inspection data
sheets, problem identification and corrective measures
reports, block evaluation reports, acceptance reports, and
final documentation. Provisions for the final storage of
all records also should be presented in the CQA plan.
This document describes these elements in detail and presents guidance on
those activities pertaining to each of the elements that are necessary to
ensure that a completed facility has been constructed to meet or exceed all
design criteria, plans, and specifications. It is intended for the use of
organizations involved in permitting, designing, and constructing hazardous
waste land disposal facilities, including treatment, storage, and disposal
facilities (i.e., landfills, surface impoundments, wastepifes).
This report was submitted in fulfillment of Contract No. 68-02-3992,
Task 032, by the Research Triangle Institute under the sponsorship of the
U.S. Environmental Protection Agency. This report covers the period October
1984 to April 1986. Work was completed as of July 1986.
vi i
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CONTENTS
Section • Page
Foreword. "Hi
Preface ............... . iv
Abstract. .............. . vi
Figures .............. x
Acknowledgments xi
1.0 Introduction. 1
1.1 Document Purpose 1
1.2 Applicability to Existing Regulations and Minimum
Technology Guidance 1
1.3 Document Users ...... . 2
1.4 Key Concepts 3
1.4.1 Management of Construction Quality 3
1.4.2 Construction Quality Assurance Program. ..... 3
1.4.3 Construction Quality Assurance Plan . . 3
1.5 Document Scope and Limitations ....... 3
2.0 Elements of a Construction Quality Assurance Plan ...... 5
2.1 Responsibility and Authority ....... 6
2.1.1 Organizations Involved in CQA .......... 6
2,1.1.1 Permitting Agency. ........... 6
2.1.1.2 Facility Owner/Operator. ... 6
2.1.1.3 Design Engineer. ............ 6
2.1.1.4 CQA Personnel 7
2.1.1.5 Construction Contractor 8
2.1.2 Project Meetings 9
2.1.2.1 Preconstruction CQA Meeting 9
2.1.2.2 Daily Progress Meetings 10
2.1.2.3 Problem or Work Deficiency Meetings. . . 10
2.2 Personnel Qualifications ..... 10
2.2.1 CQA Officer 10
2.2.2 CQA Inspection Personnel 11
2.2.3 Consultants , 11
2.3 Inspection Activities 11
2.3.1 General Preconstruction Activities 12
2.3.2 Foundations ......... 12
2.3.2.1 Preconstruction 13
2.3.2.2 Construction . 13
2.3.2.3 Postconstruction 15
2.3.3 Dikes 15
2.3.3.1 Preconstruction 15
2.3.3.2 Construction 16
2.3.3.3 Postconstruction 17
2.3.4 Low-Permeability Soil Liners 18
2.3.4.1 Preconstruction 18
2.3.4.2 Construction 24
2.3.4.3 Postconstruction ..... 27
viii
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Section
CONTENTS
Page
2.3.5 Flexible Membrane Liners 28
2.3.5.1 Preconstructlon . 28
2.3.5.2 Construction . , . . 33
2.3.5.3 Postconstructlon ............ 38
2.3.6 Leachate Collection Systems ........... 39
2.3.6.1 Preconstructlon. 39
2.3.6.2 Construction . ...... 40
2.3.6.3 Postconstructfon ............ 47
2.3.7 Final Cover Systems . ...... 47
2.3.7.1 Preconstructlon 48
2.3.7.2 Construction . ..... 48
2.3.7.3 Postconstructlon 53
2.4 Sampling Strategies 54
2.4.1 Sampling Units and Sample Elements. ....... 55
2.4.2 Types of Sampling Strategies 56
2.4.2.1 100-Percent Inspection ......... 56
2.4.2.2 Judgmental Sampling 56
2.4.2.3 Statistical Sampling ..... 57
2.4.3 Selection of Sample Size. 59
2.4.3.1 Judgmental Method 59
2.4.3.2 Statistical Methods 60
2.4.4 Treatment of Outliers 65
2.4.5 Corrective Measures ....... 66
2.4.6 Control Charts 66
2.5 Documentation 69
2.5.1 Daily Recordkeeping 69
2.5.1.1 Daily Summary Report 69
2.5.1.2 Inspection Data Sheets . 72
2.5.1.3 Problem Identification and Corrective
Measures Reports ............ 73
2.5.2 Photographic Reporting Data Sheets. ....... 74
2.5.3 Block Evaluation Reports. . ..... 75
2.5.4 Acceptance of Completed Components. ....... 75
2.5.5 Final Documentation 76
2.5.5.1 Responsibility and Authority 76
2.5.5.2 Relationship to Permitting Agencies. . 76
2.5.6 Document Control 76
2.5.7 Storage of Records 77
References. 78
Appendix A. Inspection Methods Used During the Construction
of Hazardous Waste Land Disposal Facilities 83
IX
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FIGURES
Number Page
2-1 Schematic of a test fill 22
2-2 Example of a test fill equipped to allow quanti-
fication of underdrainage. 23
2-3 Control charts: individual and moving average .... 68
2-4 Rejection chart: density measurements for dam
core compaction control 70
2-5 Frequency diagram: density measurements for dam core
compaction control ... ..... 71
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ACKNOWLEDGMENTS
This report was prepared by C. M. Northeim and R. S. Truesdale of th«
Research Triangle Institute (RTI), Research Triangle Park, North Carolina,
under Contract Number 68-02-3992, Task 032. The U.S. Environmental Protection
Agency (EPA) Project Officer was Jonathan G. Herrmann of the Hazardous
Waste Engineering Research Laboratory, Cincinnati, Ohio. Substantial input
and guidance also were received from Alessi D. Otte of the Office of Solid
Waste and Emergency Response.
The authors wish to thank Robert P. Hartley, Robert E. Landreth,
Dr. Walter E. Grube, Jr., Daniel Greathouse, and Kent Anderson, also of
EPA, for their advice and technical guidance in preparing the document.
The authors would like to acknowledge the following individuals who
have contributed information to sections of this document and earlier
drafts:
Doug Allen of E. C. Jordan Company
David Anderson of K. W. Brown & Associates, Inc.
Salvatore Arlotta of Wehran Engineering
Jeffrey Bass of Arthur D. Little, Inc.
Dirk Brunner of E. C. Jordan Company
Peter Fleming of ATEC Associates, Inc.
Jack Fowler of USAE Waterways Experiment Station
J. P. Giroud of GeoServices, Inc., Consulting Engineers
James Harmston of American Foundations
Louis R. Hovater of Hovater-MYK Engineers
Walter Ligget of National Bureau of Standards
R. J. Lutton of USAE Waterways Experiment Station
John G. Pacey of EICON Associates
S. Joseph Spigolon, Engineering Consultant
James Withiam of D'Appolonia Consulting Engineers, Inc.
Leonard 0. Yamamoto of Hovater-MYK Engineers
The authors also acknowledge the Waste Management, Inc., "Quality Assurance
Manual for Installation of High Density Polyethylene Geomembranes" that
served as a reference during the preparation of this document.
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1.0 INTRODUCTION
1.1 DOCUMENT PURPOSE
This Technical Guidance Document (TGD) presents guidance for preparing
a site-specific construction quality assurance (CQA) plan for a hazardous
waste land disposal facility (i.e., landfill, surface impoundment, or
wastepile). The guidance describes the elements of a CQA plan that the
U.S. Environmental Protection Agency (EPA) believes will ensure that a
completed facility has been constructed to meet or exceed all design criteria,
plans, and specifications.
EPA believes that a site-specific CQA plan that addresses the components
of a hazardous waste land disposal facility is needed and recommends that
this plan be included as part of the permit application for such a facility.
It should be stressed, however, that methods and procedures described in
this document are guidance, not regulations; alternative methods and proced-
ures may be selected by the owner/operator. The hazardous waste land
disposal facility components discussed in this document include:
Foundations
Dikes
Low-permeability soil liners
Flexible membrane liners (FMLs)
Leachate collection systems (LCSs)
Final cover systems.
Development of comprehensive information on CQA for these components
is being prepared by the Hazardous Waste Engineering Research Laboratory
(HWERL) of the Office of Research and Development (ORD) in close cooperation
with the Office of Solid Waste and Emergency Response (OSWER). HWERL is
using a two-phased approach to meet the goals of EPA's CQA program. This
document is the result of Phase One of this approach. Phase Two will
develop additional information on construction quality assurance through
research that will gather and present information on areas not addressed in
detail in Phase One.
1.2 APPLICABILITY TO EXISTING REGULATIONS AND MINIMUM TECHNOLOGY GUIDANCE
The Hazardous and Solid Waste Amendments of 1984 (HSWA) require that
the owner/operator of an interim status hazardous waste land disposal
1
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facility who constructs a new unit, laterally expands an existing unit, or
replaces an existing unit must comply with the minimum technological require-
ments of §3004(o) with respect to waste received after May 8, 1985.
One aspect of the facility owner/operator's burden of demonstrating
good faith compliance with EPA's regulations is presenting evidence that
the facility was designed and instailed in accordance with those regula-
tions. As part of this demonstration, a site-specific CQA plan should be
prepared and submitted to the permitting agency as part of the permit
application. This CQA plan should clearly demonstrate that regulatory
requirements for the inspection of liners and cover systems (as appropriate)
of landfills, surface impoundments, and wastepiles (40 CFR 264.303, 264.226,
and 264.254) will be met. The implementation of the CQA plan is demonstrated
by CQA documentation. Specific elements that should be included in the CQA
plan are identified and addressed in EPA's technical guidance on double
liner systems (EPA, 1985) and are discussed in greater detail in Section 2.0
of this document.
A copy of the site-specific CQA plan and CQA documentation should be
retained at the facility by the owner/operator. It may be reviewed during
a site inspection by the permitting agency and will be the chief means for
the facility owner/operator to demonstrate to the permitting agency that
EPA's technical guidance for installing a double liner system has been
followed. Therefore, it is extremely important that the owner/operator
document CQA activities to clearly demonstrate that he followed the EPA
regulations and technical guidance on double liner systems when installing
the liners and leachate collection systems.
1.3 DOCUMENT USERS
This document is intended for use by organizations involved in per-
mitting, designing, and constructing hazardous waste land disposal facil-
ities.
Permitting agencies (i.e., State agencies and EPA) may use this document
when reviewing site-specific CQA plans to help establish the completeness
of a submitted CQA plan and to ensure its implementation. This document
also may be used by facility owner/operators to make certain that all CQA
elements are addressed in their permit applications by helping them criti-
cally review a site-specific CQA plan prepared by their supporting organiza-
tions (e.g., design engineer, CQA personnel).
A supporting organization preparing a site-specific CQA plan may use
this document as a guide, and it will enable them to identify weaknesses
and confirm strengths in their own standard CQA programs for hazardous
waste land disposal facilities. Construction contractors nay use this
document as a reference that outlines the inspection activities to which
their work may be subjected or as guidance for implementing their own
construction quality control plans.
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1.4 KEY CONCEPTS
1.4.1 Management of Construction Quality
As applied to this TGD, the management of construction quality is the
responsibility of the facility owner/operator and involves using scientific
and engineering principles and practices to ensure that a hazardous waste
land disposal facility has been constructed to meet or exceed all design
criteria, plans, and specifications. This management activity begins prior
to construction, continues throughout construction, and ends when the
completed facility is accepted by the owner/operator. Managing construction
quality involves both construction quality control (CQC), a planned system
of inspections that are used to directly monitor and control the quality of
a construction project, and construction quality assurance (CQA), a planned
system of activities that provide assurance that the facility was constructed
as specified in the design.
CQC is performed by the construction contractor(s) and consists of
inspections necessary to control the quality of the constructed or installed
component. These activities are completely independent of the CQA activities
described in this document. Although specific recommendations for CQC
practices are beyond the scope of this document, CQC is important as the
first step in managing construction quality. CQA is performed independently
of CQC. It includes inspections, verifications, audits, and evaluations of
materials and workmanship necessary to determine and document the quality
of the constructed facility.
1.4.2 Construction Quality Assurance Program
The CQA program discussed in this document is EPA's approach to CQA
for hazardous waste land disposal facilities. This program is divided into
two parts: (1) regulations that specify the use of construction quality
assurance for hazardous waste land disposal facilities, and (2) guidance
that presents the elements of a site-specific CQA plan. This document is
the result of Phase One of the second part of EPA's CQA program.
1.4.3 Construction Quality Assurance Plan
This TGD provides guidance for preparing a CQA plan—the facility
owner/operator's site-specific written response to EPA's CQA program. The
CQA plan should include a detailed description of all CQA activities that
will be used to manage construction quality. The CQA plan documents the
owner/operator's approach to CQA and should be tailored to the specific
facility to be constructed. The facility owner/operator1 s CQA plan should
be included in the permit application, and the permitting agency should
review the plan for completeness and confirm that it is implemented.
1.5 DOCUMENT SCOPE AND LIMITATIONS
This document is a compilation of information on construction quality
assurance and is limited in its scope and function in the following ways.
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First, although the document provides information on state-of-the-art CQA
for hazardous waste land disposal facilities, it is not necessarily compre-
hensive. Researching and evaluating all possible sources of effective CQA
guidance and procedures were beyond the scope of this effort. Second, this
document should not be construed to present design procedures for hazardous
waste land disposal facilities. That remains the responsibility of the
design engineer and should be based on site-specific conditions.
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2.0 ELEMENTS OF A CONSTRUCTION QUALITY ASSURANCE PLAN
The facility owner/operator should prepare a written CQA plan as part
of the permit application. Although the overall content of the CQA plan
will depend on the site-specific conditions for the proposed hazardous
waste land disposal facility, at a minimum several elements should be
included in the plan. These elements are summarized below,
Responsibility and Authority—The responsibility and author-
ity of organizations and key personnel (by title) involved
in permitting, designing, and constructing the hazardous
waste land disposal facility should be described in the CQA
plan.
CQA Personnel Qualifications—The qualifications of the CQA
officer and supporting CQA inspection personnel should be
presented in the CQA plan in terms of the training and
experience necessary to fulfill their identified responsi-
bilities.
Inspection Activities—The observations and tests that will
be used to ensure that the construction or installation
meets or exceeds all design criteria, plans, and specifica-
tions for each hazardous waste land disposal facility component
should be described in the CQA plan.
Sampling Strategies—The sampling activities, sample size,
methods for determining sample locations, frequency of
sampling, acceptance and rejection criteria, and methods for
ensuring that corrective measures are implemented as addressed
in the design criteria, plans, and specifications should be
presented in the CQA plan.
Documentation—Reporting requirements for CQA activities
should be described in detail in the CQA plan. This should
include such items as daily summary reports, inspection data
sheets, problem identification and corrective measures
reports, block evaluation reports, acceptance reports, and
final documentation. Provisions for the final storage of
all records also should be presented in the CQA plan.
Each of these elements is described in greater detail in the following
subsections.
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2.1 RESPONSIBILITY AND AUTHORITY
2.1,1 Organizations Involved In CQA
The principal organizations involved in permitting, designing, and
constructing a hazardous waste land disposal facility include the permitting
agency, facility owner/operator, design engineer(s), CQA personnel, and
construction contractor(s). Except for the permitting agency, the principal
organizations will not necessarily be completely independent of each other:
the facility owner/operator also may be the construction contractor; the
CQA personnel may be employees of the facility owner/operator, of the
design engineer, or of an independent firm. Regardless of the relationships
among the organizations, it is essential that the areas of responsibility
and lines of authority for each organization be clearly delineated as the
first element of the CQA plan. This will help establish the necessary
lines of communication that will facilitate an effective decisionmaking
process during implementation of the site-specific CQA plan. It is also
essential that the organization performing CQA operates independently of
and is not responsible to the organizations involved in constructing the
facility.
2.1.1.1 Permitting Agency—
The permitting agency (i.e., State agencies, EPA) is authorized by law
to issue a permit for the construction of a hazardous waste land disposal
facility. It is the responsibility of the permitting agency to review the
facility owner/operator's permit application, including the site-specific
CQA plan, for compliance with the agency's regulations and to make a decision
to issue or deny a permit based on this review. The permitting agency will
have the responsibility and authority to review and accept or reject any
design revisions or requests for variance that are submitted by the facility
owner/operator after the permit is issued. The agency also has the respon-
sibility and authority to review all CQA documentation during or after
facility construction to confirm that the approved CQA plan was followed
and that the facility was constructed as specified in the design.
2.1.1.2 Facility Owner/Operatoi—
The facility owner/operator is responsible for the design, construction,
and operation of the hazardous waste land disposal facility. This responsi-
bility includes complying with the requirements of the permitting agency in
order to obtain a permit and assuring the permitting agency, by the submission
of CQA documentation, that the facility was constructed as specified in the
design. The owner/operator has the authority to select and dismiss organi-
zations charged with design, CQA, and construction activities. The owner/
operator also has the authority to accept or reject design plans and speci-
fications, CQA plans, reports and recommendations of the CQA officer, and
the materials and workmanship of the contractor. If the owner and operator
are different organizations, the facility owner is ultimately responsible
for the above activities.
2.1.1.3 Design Engineer—
The design engineer's primary responsibility is to design a hazardous
waste land disposal facility that fulfills the operational requirements of
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the facility owner/operator and the performance requirements of the permit-
ting agency. Design activities may not end until the facility is completed;
the design engineer may be requested to change some component designs if
unexpected site conditions are encountered or changes in construction
methodology occur that could adversely affect facility performance, CQA
provides assurance that these unexpected changes or conditions will be
detected, documented, and addressed during construction.
Additional responsibility and authority may be delegated to the design
engineer by the expressed consent (i.e., a contractual agreement) of the
facility owner/operator. Additional responsibility and authority may
include formulating and implementing a site-specific CQA plan, periodic
review of CQA documentation, modifying construction site activity, and
specifying specific corrective measures in cases where deviation from the
specified design or failure to meet design criteria, plans, and specifica-
tions is detected by CQA personnel.
2.1.1.4 CQA Personnel--
The overall responsibility of the CQA personnel is to perform those
activities specified in the CQA plan (e.g., inspection, sampling, documenta-,
tion). At a minimum, CQA personnel should include a CQA officer and the
necessary supporting CQA inspection personnel. The specific responsi-
bilities and authority of each of these individuals should be defined
clearly in the CQA plan and in the associated contractual agreements with
the facility owner/operator. Specific responsibilities of the CQA officer
may include:
Reviewing design criteria, plans, and specifications for
clarity and completeness so that the CQA plan can be imple-
mented
Educating CQA inspection personnel on CQA requirements and
procedures
Scheduling and coordinating CQA inspection activities
Directing and supporting the CQA inspection personnel in
performing observations and tests by:
submitting blind samples (knowns, duplicates, and
blanks) for analysis by the CQA inspection personnel
and one or more independent laboratories
confining that regular calibration of testing equipment
is properly conducted and recorded
confirming that the testing equipment, personnel, and
procedures do not change over time or making sure that
any changes do not adversely impact the inspection
process
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confirming that the test data are accurately recorded
and maintained (this may involve selecting reported
results and backtracking them to the original observa-
tion and test data sheets)
verifying that the raw data are properly recorded,
validated, reduced, summarized, and interpreted
Providing to the facility owner/operator reports on the
inspection results including:
review and interpretation of all data sheets and reports
identification of work that the CQA officer believes
should be accepted, rejected, or uncovered for observa-
tion, or that may require special testing, inspection,
or approval
rejection of defective work and verification that
corrective measures are implemented
Verifying that a contractor's construction quality control
plan is in accordance with the site-specific CQA plan
At the owner/operator's request, reporting to the contractor
results of all observations and tests as the work progresses
and interacting with the contractor to provide assistance in
modifying the materials and work to comply with the specified
design
For the supporting CQA inspection personnel, specific responsibilities
My include:
Performing independent onsite inspection of the work in
progress to assess compliance with the facility design
criteria, plans, and specifications
Verifying that the equipment used in testing meets the test
requirements and that the tests are conducted according to
the standardized procedures defined by the CQA plan
Reporting to the CQA officer results of all inspections
including work that is not of acceptable quality or that
fails to meet the specified design.
2.1.1.5 Construction Contractoi—
It is the responsibility of the construction contractor to construct
tN hazardous watte land disposal facility in strict accordance with design
cHttria, plans, and specifications, using the necessary construction
procedures and techniques. This responsibility may be expanded, as part of
th* contractual agreement with the facility owner/operator, to include
fanmlating and implementing a formal plan for construction quality control.
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2.1.2 Project Meetings
Periodic meetings held during the life of the project will strengthen
responsibility and authority by enhancing communication between personnel
responsible for designing, inspecting, and constructing a hazardous waste
land disposal facility. Conducting periodic project meetings is the respon-
sibility of the facility owner/operator; he may delegate that responsibility
to one of his supporting organizations (e.g., design engineer). Regardless
of who conducts them, periodic project meetings benefit all those involved
with the facility by ensuring familiarity with facility design, construction
procedures, and any design changes. Examples of the types of meetings that
may be held are discussed in the following subsections.
2.1.2.1 Reconstruction CQA Meeting--
A meeting should be held to resolve any uncertainties following the
completion of the facility design, completion of the site-specific CQA
plan, and award of the construction contract. The facility owner/operator,
design engineer, CQA personnel, and construction contractor should all be
present. The topics of this meeting include but are not limited to:
Providing each organization with all relevant CQA documents
and supporting information
Familiarizing each organization with the site-specific CQA
plan and its role relative to the design criteria, plans,
and specifications .
Determining any changes to the CQA plan that are needed to
ensure that the facility will be constructed to meet or
exceed the specified design
Reviewing the responsibilities of each organization
Reviewing lines of authority and communication for each
organization
Discussing the established procedures or protocol for observa-
tions and tests including sampling strategies
Discussing the established procedures or protocol for handling
construction deficiencies, repairs, and retesting
Reviewing methods for documenting and reporting inspection
data
Reviewing methods for distributing and storing documents and
reports
Reviewing work area security and safety protocol
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Discussing procedures for the location and protection of
construction materials and for the prevention of damage of
the materials from inclement weather or other adverse events
Conducting a site walk-around to review construction material
and inspection equipment storage locations.
The meeting should be documented by a designated person, and minutes should
be transmitted to all parties.
2.1.2.2 Daily Progress Meetings—
A progress meeting should be held daily at the work area just prior to
commencement or following completion of work. At a minimum, the meeting
should be attended by the construction contractor and the CQA personnel.
The purpose of the meeting is to:
Review the previous day's activities and accomplishments
Review the work location and activities for the day
Identify the contractor's personnel and equipment assignments
for the day
Discuss any potential construction problems.
This meeting should be documented by a member of the CQA inspection personnel,
2.1.2.3 Problem or Work Deficiency Meetings—
A special meeting may be held when and if a problem or deficiency is
present or likely to occur. At a minimum, the meeting should be attended
by the construction contractor and CQA personnel. The purpose of the
meeting is to define and resolve a problem or recurring work deficiency in
the following manner:
Define and discuss the problem or deficiency
Review alternative solutions
Implement a plan to resolve the problem or deficiency.
The meeting should be documented by a member of the CQA inspection personnel.
2.2 PERSONNEL QUALIFICATIONS
The CQA plan should identify the required qualifications of the CQA
officer and the CQA inspection personnel and describe their expected duties,
2.2.1 CQA Officer
The CQA officer is that individual assigned singular responsibility
for all aspects of the CQA plan implementation. The CQA officer is respon-
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sible to the facility owner/operator and should function independently of
the owner/operator, design engineer, and construction contractor. The
location of the CQA officer within the overall organizational structure of
the project, including the facility owner/operator, design engineer, con-
struction contractor, and permitting agencies, should be clearly described
within the CQA plan as noted in the previous discussion on responsibility
and authority.
The CQA officer should possess adequate formal academic training in
engineering, engineering geology, or closely associated disciplines and
sufficient practical, technical, and managerial experience to successfully
oversee and implement construction quality assurance activities for hazard-
ous waste land disposal facilities. Many of the responsibilities of a CQA
officer may also require that he or she be a registered Professional Engineer
or the equivalent. Because the CQA officer may have to interrelate with
all levels of personnel involved in the project, good communication skills
are essential. The CQA officer should be expected to ensure that communica-
tion of all CQA-related matters is conveyed to and acted upon by the affected
organizations.
2.2.2 CQA Inspection Personnel
The CQA inspection personnel should possess adequate formal training
and sufficient practical technical and administrative experience to execute
and record inspection activities successfully. This should include demon-
strated knowledge of specific field practices relating to construction
techniques used for hazardous waste land disposal facilities, all codes and
regulations concerning material and equipment installation, observation and
testing procedures, equipment, documentation procedures, and site safety.
2.2.3 Consultants
Authorities in engineering geology, geotechnical engineering, civil
engineering, and other technical disciplines may be called in from external
organizations in the event of unusual site conditions or inspection results.
The CQA plan should present detailed documentation of consultant qualifica-
tions when expert technical judgments are obtained and used as a basis for
decision in some aspect of construction quality assurance. Expert opinions
should not be used as a substitute for objective data collection and inter-
pretation when suitable observations and test procedures are available.
2.3 INSPECTION ACTIVITIES
The third element of the CQA plan should describe the inspection
activities (observations and tests) that will be performed by the CQA
personnel during hazardous waste land disposal facility construction. The
scope of this discussion should address only the construction and installa-
tion of all facility components and the manufacture/fabrication of various
components and subcomponents when pertinent. It is assumed that the site
has been characterized adequately, including evaluation of the hydrogeologic
environment. It is also assumed that a site-specific facility design has
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been prepared that meets regulatory requirements and is acceptable to the
facility owner/operator and that this design has been evaluated to ensure
its technical correctness and feasibility.
This section addresses the inspection activities that are necessary to
ensure that the facility has been constructed to meet or exceed all design
criteria, plans, and specifications. The first subsection addresses general
preconstruction activities applicable to all facility components. The
subsequent subsections address each facility component separately and are
further subdivided into sections on preconstruction, construction, and
postconstruction inspection activities unique to each component. Specific
test methods that may be used to inspect the components of a hazardous
waste land disposal facility are listed and referenced in Appendix A.
2.3.1 General Preconstruction Activities
The CQA officer should review for clarity the design drawings and
specifications for the hazardous waste land disposal facility to be con-
structed. The design criteria, plans, and specifications need to be under-
standable to both the CQA personnel and the construction contractor. If
the design is deemed unclear by the CQA officer, it should be returned to
the design engineer for clarification or modification.
It may be necessary to include a preconstruction training program for
the CQA inspection personnel in the site-specific CQA plan. As stated by
the U.S. Department of the Army's Construction Control for Earth and Rock-
Fill Dams (1977):
Preconstruction instructions and training should be given to
field inspection personnel to acquaint them with design concepts
and to provide them with a clear understanding of expected condi-
tions, methods of construction, and the scope of plans and specifi-
cations. This may be done by training sessions, preferably with
design personnel present, using a manual of written instructions
prepared especially for field personnel, to discuss engineering
considerations involved, and to explain control procedures and
required results.
The ultimate decision on whether to implement a preconstruction training
program rests with the facility owner/operator but may be influenced by
recommendations of the supporting organizations.
2.3,2 Foundations
The foundations for hazardous waste land disposal facilities should
provide structurally stable subgrades for the overlying facility components.
The foundations also should provide satisfactory contact with the overlying
liner or other system component. In addition, the foundations should
resist settlement, compression, and uplift resulting from internal or
external pressures, thereby preventing distortion or rupture of overlying
facility components.
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It is assumed that, before construction, adequate site investigations
have been conducted and the foundation design has been developed, to
accommodate the expected site conditions. The following subsections describe
the inspection activities that are necessary to ensure that a foundation is
constructed to meet or exceed the specified design. Specific tests mentioned
in this section are listed and referenced in Appendix A,
2,3.2.1 Reconstruction—
It is especially important for all CQA personnel and the construction
contractor(s) to review site investigation information to familiarize
themselves with the expected site conditions upon which the facility designs
were based. This will help ensure that the CQA personnel will be able to
identify any unexpected site conditions that may be encountered during
foundation construction. Unexpected site conditions may necessitate modifi-
cations of the facility design and construction procedures by the design
engineer and the construction contractor to ensure component performance.
2.3.2.2 Construction--
To ensure that the design objectives for the foundation are met,
inspection activities during construction of the foundation should include
the following (U.S. Army, 1977):
Observations of soil and rock surfaces for adequate filling
of rock joints, clay fractures, or depressions, and removal
and filling of sand seams
Measurements of the depth and slope of the excavation to
ensure that it meets design requirements
Observations to ensure proper placement of any recessed
areas for collection or detection pipes and sumps
Tests and observations to ensure the quality of compacted
fill
Observations of stripping and excavation to ensure that
there are no moisture seeps and that all soft, organic, and
otherwise undesirable materials are removed. Proof-rolling
with heavy equipment can be used to detect soft areas likely
to cause settlement. Consistency of the foundation soil may
be checked with a hand penetrometer, field vane shear test,
or similar device.
In addition, when the foundation is to serve as the lower bedding layer for
an FML, inspection activities should include the following:
Observations to ensure the removal of objects (e.g., roots
and rocks) that could penetrate the FML
Observations to ensure the quality of any specified herbicide
and to ensure that it is applied uniformly as specified to
the foundation soil
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Observations and tests to ensure that the surface is properly
compacted, smooth, uniform, and consistent with.design
grades.
Inspection activities during foundation construction will help ensure
that the facility meets or exceeds the specified design by preventing or
detecting the following:
Sidewall slope failure from moisture seeps, weak foundation
soil, or sidewall slopes that are steeper than specified
Puddling or ponding on the foundation base, improper function-
ing of the leachate collection systems (LCS) resulting from
less than specified bottom slopes, and the unspecified
placement of recesses for LCS pipes and sumps
Flexible membrane liner damage from an improperly prepared
foundation (e.g., removing penetrating objects and sterilizing
the soil)
Foundation settlement due to soft areas in the foundation
base. Excessive differential settlement can result in
distortion or rupture of overlying facility components
Regions of high permeability in the foundation base, from
ungrouted joints or from the presence of high-permeability
foundation materials. Permeable zones can compromise the
ability of the foundation to serve as an additional barrier
to leachate migration and can present pathways for seepage
into the facility, causing blowout of the liner during
subsequent facility construction.
Continuous visual observation of the construction process is a major
means of ensuring that the foundation is constructed to meet or exceed the
specified design. Surveying will be necessary to ensure that facility
dimensions, side slopes, and bottom slopes are as specified in the design.
Visual-manual soil identification techniques and index property tests may
be used to monitor foundation soil composition. Cohesive soil consistency
may be checked in the field with a penetrometer, a hand-held vane shear
device, or other suitable field-expedient measurement device (see Appendix
A). These field-expedient methods give only approximate values. They are
usually sufficient for construction control or site material verification,
but they are not accurate or precise enough to be used for acceptance
testing; standard laboratory tests [such as consolidated undrained (CU) or
unconsolidated undrained (UU) triaxial or unconfined compression, depending
on foundation soil conditions] may be used for acceptance testing. Compac-
tion of soil backfill is controlled as described in Section 2.3.3.2.1.
Further information on quality control of foundations may be found in
Spigolon and Kelley (1984), USSR (1974), and U.S. Army (1977).
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2.3.2.3 Postconstruction—
Foundation completion tests include testing and proof-roll ing to
ensure uniform foundation soil consistency, visually inspecting foundation
surfaces, and surveying to check elevations, slopes, and foundation bound-
aries.
2.3.3 Dikes
The purpose of a dike in a hazardous waste landfill, surface impound-
ment, or wastepile is to function as a retaining wall, resisting the lateral
forces of the stored wastes. It is the aboveground extension of the founda-
tion, providing support to the overlying facility components. Dikes therefore
must be designed, constructed, and maintained with sufficient structural
stability to prevent their failure. Dikes also may be used to separate
cells for different wastes within a large landfill or surface impoundment.
Dikes may be constructed of soil material that is compacted as necessary
to a specified strength, unlike soil liner material, which is compacted for
low permeability. Materials other than soil may be used to construct
dikes, as long as the design of the dike accommodates the particular material
properties and proper installation procedures are followed. Drainage
layers and structures may be included in the dike design if conditions
warrant control of seepage. (Although seepage through the dike should be
prevented by the liner system, a dike must be designed to maintain its
integrity if the liner fails and seepage occurs.}
The following subsections describe the inspection activities that are
necessary to ensure that a dike is constructed to meet or exceed the specified
design. Specific tests mentioned in the following subsections are listed
and referenced in Appendix A.
2.3.3.1 Reconstruction—
Preconstruction inspection activities for dikes should include inspec-
tion of the prepared foundation and inspection of incoming materials.
These activities also may include construction of a test fill.
2.3.3.1.1 Materials inspection--Haterials to be used for the dike
should be inspected. It is especially important that all dike materials
are uniform and as specified to ensure that no soft or structurally weak
materials (e.g., organic materials) are included in the dike. Procedures
for inspecting soil materials are discussed in Section 2.3.4.1.1.
2.3.3.1.2 Test fill constructipn--A test fill may be constructed to
verify that the sped fled sol 1 density/moisture content/compactive effort/
strength relationships hold for field conditions and to determine construc-
tion equipment suitability for dike construction. Test fill compaction is
described in Section 2.3.4.1.2. Unlike soil liner test fills, permeability
tests are not necessary on dike test fills; strength tests are necessary to
confirm the relationship between moisture and density measurements and
strength. Tests for shear strength (e.g., consolidated or unconsolidated,
undrained triaxial tests or unconfined compressive strength) are appro-
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priate for cohesive soils. Selection of appropriate test method(s) should
be based on the expected site-specific conditions of the dike during and
after construction. Field-expedient methods of measuring cohesive soil
consistency (e.g., penetrometers or vane shear devices) may be used to
estimate unconfirmed compressive strength; however, results of these tests
should be confirmed in the test fill using appropriate laboratory methods.
2.3.3.1.3 Foundation preparation—To ensure that the foundation has
adequate bearing capacity to support the dike, foundation soil analyses
should include strength tests [e.g., unconfined compression or undrained
(consolidated or unconsolidated) triaxial tests]; compressive strength
correlations with standard penetration tests or vane shear tests may be
used for construction control. If soft foundation conditions necessitate
excavation and replacement of foundation soils, the excavation of the
undesirable material and the placement and compaction of soil in the excava-
tion should be monitored closely and continuously by the CQA inspection
personnel. The compacted fill material should be inspected to ensure that
it is uniform and as specified. Section 2.3.3.2.1 describes inspection
procedures for compacted fill. Foundation inspection procedures are des=
cribed in more detail in Section 2.3.2.
2.3.3.2 Construction-
Dike construction involves standard earthwork construction practices.
Dike construction activities may include compacted fill placement and
compaction, drainage system construction, and implementation of erosion
control measures. Adequate CQA during dike construction will identify
problems resulting from inadequate construction methodologies or materials
that could result in dike failure from slope instability, settlement,
seepage problems (e.g., piping, pore pressure changes), or erosion.
2.3.3.2.1 Compacted f111 construction—Compacted fill may be present
in the dike core or may constitute the entire dike. Inspection activities
that should be conducted during fill emplacement, conditioning, and compac-
tion include:
Testing of fill material characteristics (see Section
2.3.4.1.1), permeability, clod size, and frost suscepti-
bility may not be necessary for dike materials
Measurement of loose lift thickness
Observation of clod size reduction and material homogeniza-
tion operations (if applicable)
Testing of water content (if applicable)
Observation of type of compaction equipment, number of
passes, and uniformity of compaction coverage
Testing of the density of the compacted fill
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Observation of scarification and connection between compacted
fill lifts (if applicable).
Inspection activities for compacted fill, including observations and specific
tests, are discussed in more detail in Section 2.3.4.2.
Specifications for compaction of dikes may differ from those for
low-permeability soil liners because the former are compacted for strength
and the latter are compacted to achieve low permeability. CQA inspection
activities are similar, however, except that permeability tests on undis-
turbed samples are not required for dikes. In addition, strength tests
generally are more important for dikes than they are for soil liners. As
with soil liners, close visual observation during all phases of construction
is a critical aspect of CQA.
2.3.3.2.2 Dike she! 1 construction—Compacted fill may be used to for*
the dike shells surrounding a compacted core. As with any compacted fill,
uniformity of the material is very important. CQA inspection activities
that should be conducted during dike shell installation include:
Testing of fill material characteristics
Measurement of loose lift thickness
Testing compacted fill water content and compacted fill
density
Observation of equipment type, number of passes, and routing
Measurement of dike slopes.
CQA activities for dike shells should be directed toward ensuring that
the shear strength and compressibility required by the specified design art
achieved.
2.3.3.2.3 Drainage systems installation—Installation procedures and
equipment for dike drainage systems are similar to those for leachate
collection systems. The observations and tests that are necessary to
monitor the installation of drainage system components are discussed in
Section 2.3.6.
2.3.3.2.4 Erosion control measures—Erosion control measures are
applied to the outer slopes of dikes and may include berms and vegetative
covers. Inspection activities necessary for ensuring the quality of erosion
control measures are the same as those for topsoil and vegetation subcoapo-
nents of cover systems (see Sections 2.3.7.2.7 and 2.3.7.2.8).
2.3.3.3 Postconstruction—
Surveys and visual observations should be conducted to ensure that the
dimensions of the completed dike are as specified. Dike slopes are the
most important items to check; if slopes are too steep, they may be unstable
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and eventually could fail. Other Hems to be checked include berm width
(if a berm is part of the dike), crest width, overall height, thickness,
and areal dimensions. Finally, vegetative cover, when specified, should be
inspected at regular intervals to ensure that vegetation is properly estab-
lished.
2,3.4 low-Permeability Soil Liners
The purpose of a low-permeability soil liner depends on the overall
liner system design. In the cases of single liners constructed of soil or
double liner systems with soil secondary liners, the purpose of the soil
liner is to prevent constituent migration through the soil liner. In the
case of soil liners used as the lower component of a composite liner, the
soil component serves as a protective bedding material for the FML upper
component and minimizes the rate of leakage through any breaches in the FML
upper component. An objective shared by all low-permeability soil liners
is to serve as long-term, structurally stable bases for all overlying
materials.
Although natural and manraade soil amendments (e.g., soil-cement,
bentonite, lime) may be specified in a soil liner design to enhance the
performance of natural soil, CQA inspection activities for specific soil
amendments depend on the amendment and site-specific conditions. The CQA
guidance presented below for natural soil liners is also applicable to
liners constructed of amended soil. Additional CQA activities that are
necessary for amended soil liners include inspection of amendments to
ensure that their quality is as specified, observations and tests to ensure
that the specified amount of soil amendment is mixed uniformly with the
natural soil, and observations and tests to ensure that water is uniformly
added to the amended soil in the amount necessary to achieve the specified
design. ASTM standard methods to test the quality of soil cement materials
are available; these tests are referenced in Appendix A of this document.
Test methods for other soil amendments are not currently standardized. For
soil amendments for which there are no standard tests available, the owner/
operator should discuss his approach to testing and other inspection activi-
ties with the permitting agency prior to construction.
It is assumed that adequate studies have been conducted before construc-
tion to ensure that the low-permeability soil liner design meets or exceeds
regulatory requirements. These studies should include soil liner-leachate
compatibility testing; laboratory soil density, moisture content, corapactive
effort, permeability relationships; particle size distribution; Atterberg
limits; and those determinations needed for specific designs (e.g., thick-
ness, slope). The following section describes the inspection activities
that are necessary to ensure that a low-permeability soil liner is con-
structed to meet or exceed the specified design. Specific tests mentioned
in this section are listed and referenced in Appendix A.
2.3.4.1 Preconstruction--
Preconstruction CQA activities include inspection of liner materials
and test fill compaction.
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2.3.4.1.1 Material Inspection—It is necessary to inspect all liner
materials to ensure that they are uniform and as specified in the design.
Material inspection begins as a preconstruction activity and continues
throughout the liner construction period. If liner material is obtained
onsite, the inspections can be performed as the material is excavated or as
it is placed in the storage pile with unsuitable material being rejected.
If liner material is obtained offsite, inspection of the soil may be con-
ducted as it arrives at the construction site. Borrow area inspection also
may be desirable to ensure that only suitable soil liner material is trans-
ported to the site. For borrow areas containing nonuniforra materials, it
may be necessary for construction personnel to guide excavating equipment
to avoid or segregate substandard soil material as it is excavated. CQA
inspection personnel should observe segregation operations carefully and
continuously to ensure that only suitable material is retained for liner
construction.
Initial inspection of the soil can be largely visual; however, CQA
inspection personnel must be experienced with visual-manual soil classifi-
cation techniques. Changes in color or texture can be indicative of a
change in soil type or soil moisture content. The soil also should be
inspected for roots, stumps, and large rocks. In addition to observations,
a sufficient number of samples of the liner material should be tested to
ensure that material properties are within the range stated in the specifi-
cations. These properties should include at least the following:
Permeability
Soil density/moisture content relationships
Maximum clod size
Particle size distribution
Atterberg limits
Natural water content.
In regions where swelling or other unusual soils are known to occur or when
the liner may be exposed to extreme climatic conditions during or following
construction, additional properties should be addressed by the testing
program.
2.3.4.1.2 Test fill construction—A test fill is a structure used to
verify the adequacy of thelnaterials, design, equipment, and construction
procedures proposed for the soil liner. Constructing a test fill before
full-scale facility construction can minimize the potential dangers and
expense of constructing an unacceptable liner. In addition, the test fill
is a convenient tool for evaluating the most critical performance standard
of the compacted soil liner—permeability.
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The primary purpose of a test fill is to verify that the specified
soil density, moisture content, and permeability values can be achieved
consistently in the full-scale facility with the full-scale compaction
equipment and procedures. For these data to be useful, test fill compaction
and testing must be well documented, and soil materials, procedures, and
equipment used in the test fill must be the same as those used during
construction of the full-scale facility.
Several recent studies have indicated that field permeability of a
compacted soil liner may be much greater than would be predicted from
laboratory permeability tests (Herzog and Morse, 1984; Gordon and Huebner,
1983; Daniel, 1984; Boutell and Donald, 1982). Field permeability tests
appear to be much more accurate predictors of the rate at which water will
drain through a soil liner than laboratory tests. When used in conjunction
with these field tests and a detailed CQA plan, a test fill allows the
performance of the full-scale facility to be predicted with the highest
degree of confidence currently available.
Recently, several field infiltrometers have been developed and tested
to measure permeability values (Day and Daniel, 1985; Anderson et al.,
1984; Daniel and Trautwein, 1986). Although it is difficult to quantify _
exactly field permeability values that are substantially less than 1 x 10 7
cm/s (Anderson et al., 1984), it_is less difficult to verify simply that
the field permeability is 1 x io 7 cm/s or less (Day and Daniel, 1985).
Field permeability tests conducted on the actual liner can cause
substantial delays in construction and result In other problems caused by
the prolonged exposure of the liner. Therefore, field permeability tests
are usually conducted only on the test fill, thus making it necessary to
use data obtained from detailed characterization of the test fill to reach
conclusions about the permeability of the full-scale facility soil liner.
Such field tests are valid only if the test fill and full-scale facility
are constructed according to the same specifications and using the same
materials, methodology, and equipment.
The CQA plan should describe all observations and tests to be evaluated
on the test fill, including a description of the testing or sampling arrays
and replications to be conducted. Based on the parameters evaluated and
data collected from the test fill, the CQA plan should specify the tests
that will be applied to the full-scale facility liner as surrogates for
field permeability tests. Surrogate tests are a group of tests that do not
actually measure field permeability but whose results, when considered
together, can be used to estimate field permeability and hence can be used
to control this parameter during low-permeability soil liner construction.
If surrogates for field permeability tests are to be used with a high
degree of confidence, data obtained from a test fill evaluation need to
show the relationships between the actual measured permeability of areas
and lifts across the test fill and the proposed surrogate test results.
The CQA plan should describe in detail the actual surrogate observations
and tests (e.g., permeability of compacted soil samples, Atterberg limits,
particle size distribution, maximum clod size, compacted moisture content,
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compacted soil density, compactive effort, and penetrometer tests) to be
used to control and monitor the construction of the full-scale facility
liner. The procedures to be used to relate the results of these tests to
field permeability of the liner, both in the test fill and in the full-scale
facility, also must be documented.
For the test fill to represent accurately the performance of the
proposed full-scale facility, the following guidelines should be followed:
Construction of the test fill should use the same soil
material, design specifications, equipment, and procedures
proposed for the full-scale facility.
All applicable parts of the CQA plan should be followed
precisely to monitor and document test fill construction and
testing.
The test fill should be constructed at least four times
wider than the widest piece of construction equipment to be
used on the full-scale facility (Figure 2-1). This is to
ensure that there will be sufficient area to conduct all
testing after a buffer area has been left along the edges of
the test fill.
The test fill should be long enough to allow construction
equipment to achieve normal operating speed before reaching
the area within the test fill that will be used for testing
(Figure 2-1).
The test fill should be constructed with at least three
lifts to evaluate the methodology used to tie lifts together.
The test fill should be constructed to facilitate field
permeability testing [i.e., equipped with an underlying
unsaturated sand layer or free-draining geotextile to collect
and measure drainage through the soil liner (Figure 2-2)].
Undisturbed samples of the test fill liner should be collected
for laboratory permeability tests. Following collection of
undisturbed samples from the test fill, the methodology for
repairing holes in the soil liner should be evaluated. The
evaluation of a repair area should include all of those
tests previously identified for undisturbed portions of the
test fill. The methods and materials that will be used in
the repair process should be documented in the CQA plan and
should be followed during repair of testing or sampling
holes during full-scale liner construction. Performance of
repaired soil liner sections should be equal to or exceed
the performance of other liner sections.
21
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ro
^
••-•-• - -••• - '-
At least three lifts of compacted soil
A drainage layer or underdrainage collection system
J
Roller Type Equipment
L = Distance required for construction equipment to reach normal running speed
W = Distance at least four times wider than the widest piece of construction equipment
iU= Area to be used for testing
Figure 2-1. Schematic of a test fill.
-------
Backfill
r^ A—
rvs
LO
Three lifts of compacted soil
sana urair
ifc_
l»_
^"U
iage Layer —
:f<":^^Y:;''Kv.:.-'.^
^x
^
• **.V7 ) 'j-'S-jQii'-' •'" • ' ' -I" i" • " '
Original Grade
FML Liner ]
Perforated Drainage
Collection Pipe
Figure 2-2. Example of a test fill equipped to allow quantification of underdrainage.
-------
The test fill construction should include the removal and
replacement of a portion of the soil liner to evaluate the
method proposed for repair of defective portions of the
full-scale liner.
The test fill should be constructed to allow determination
of the relationship among density, moisture content, and
permeability. Field variables that can affect this relation-
ship and that must be carefully measured and controlled in
the test fill and during construction of the full-scale
liner include the following:
the compaction equipment type, configuration, and
weight
the number of passes of the compaction equipment
the method used to break down clods before compaction
and the maximum allowable clod size
the method used to control and adjust moisture content,
including equilibration time, and the quantity of water
to be used in any adjustment
the speed of the compaction equipment traveling over
the liner
the uncompacted and compacted lift thicknesses.
Additional test fills should be constructed for each borrow source and
whenever significant changes occur in the liner material, equipment, or
procedures used to construct the soil liner.
The CQA officer and the CQA inspection personnel should monitor and
thoroughly document construction and testing of the test fill. Test fill
documentation is extremely important because it provides all organizations
involved in facility construction with a complete description of the con-
struction equipment and procedures to be used during full-scale facility
construction.
2.3.4,2 Construction--
When construction of the full-scale facility liner begins, questions
should not remain about either how or with what materials the liner will be
constructed. The suitability of the selected liner material and the adequacy
of the construction equipment, construction methodology, and testing proce-
dures will have been confirmed in the test fill. The most important remaining
task necessary to construct a soil liner that meets or exceeds the specified
design will be to adhere strictly to the materials, equipment, and procedures
as verified in the test fill.
24
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There are a number of ways that improper construction practices can
result in a soil liner that is unacceptable. Guidelines to identify and
correct these improper practices in the field should be provided in the CQA
plan. These guidelines should include a combination of both continuous
observation by CQA inspection personnel during all periods and phases of
liner-related construction activity and frequent use of the tests mentioned
in Sections 2.3.4.1,1 and 2.3.4.1.2. Specifically, the CQA plan should
address the following;
Procedures and methods for observing and testing the soil
liner materials before and after placement to ensure the
following:
removal of roots, rocks, rubbish, or off-spec soil from
the liner material
identification of changes in soil characteristics
necessitating a change in construction specifications
adequate spreading of liner material to obtain complete
coverage and the specified loose lift thickness
adequate clod size reduction of liner material
spreading and incorporation of soil amendments (if
specified) to obtain uniform distribution of the speci-
fied amount throughout the liner material
adequate spreading and incorporation of water to obtain
full penetration through clods and uniform distribution
of the specified water content
procedures to be followed to adjust the soil moisture
content in the event of a significant prolonged rain or
drought during construction
prevention of significant water loss and desiccation
cracking before and after compaction.
Procedures and methods for observing and testing the soil
liner compaction process to ensure the following:
use of compaction equipment of the same type, configura-
tion, and weight as used in the test fill
use of the same equipment speed and number of equipment
passes for compaction as used in the test fill
uniformity of coverage by compaction equipment, espe-
cially at compacted fill edges, in equipment turnaround
areas, and at the tops and bottoms of slopes
25
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consistent achievement of the specified soil density,
water content, and permeability throughout each completed
lift
consistency of permeability values obtained for undis-
turbed soil liner samples with values obtained for
undisturbed samples from the test fill. Undisturbed
sample locations should be staggered from lift to lift
so holes do not align vertically.
repair of penetrations or holes resulting from the
collection of undisturbed soil samples or the use of
density or moisture probes using the same materials and
methods used for repai rs on the test fi11
adequate tying together of repaired and undisturbed
sections of the liner
use of methods sufficient to tie liner lifts together
achievement of sufficient liner strength to maintain
stable sidewalls and to supply a stable base for support-
ing overlying materials
timely placement of protective covers to prevent desicca-
tion of liner material between the installation of
lifts or after completion of the liner (where necessary)
prevention of accidental damage of installed portions
of the soil liner by equipment traffic
achievement of the specified permeability on the soil
liner sidewalls.
To ensure the above, it is necessary for the CQA inspection personnel
to observe the compaction process (including estimation of compactive
effort) continuously and to test the compacted liner at specified intervals
using specified tests (see Sections 2.3.4,1.1 and 2.3.4.1.2). The plan for
conducting these tests, including methods for determining sampling frequency
and location, should be described in detail in the CQA plan. Section 2.4
discusses strategies for determining sampling frequency and location as
well as methods for using test data to determine whether to accept or
reject completed work. Regardless of the methods used in the development
of sampling strategies, they should be described clearly and completely in
the CQA plan, along with the rationale for using them.
The compaction process can be affected by climate. Construction
specifications often place restrictions on work performed during and just
after a rainfall, during very hot or windy conditions, or during freezing
weather. For clay soil, wet or freezing weather can alter the soil water
content to the point that close control of the compaction process may not
26
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be possible. Movement of the construction equipment may be severely affected.
As soil temperature falls, more compactive effort must be applied to achieve
the same density (Johnson and SaTlberg, I960). Freezing can alter soil
structure, causing sloughing of liner materials on the sidewalls or an
increase in permeability. In very dry weather, the water content of each
surface compacted fill layer can also be altered in a very short time by
drying, making continuous watering and blending necessary. Atmospheric
conditions should be observed and recorded by CQA inspection personnel, and
appropriate actions should be taken when unsuitable weather conditions
exist.
Inspection activities during the construction of low-permeability soil
liners will help ensure that the facility is constructed as designed by
preventing or detecting the following:
Regions of higher-than-specified liner permeability caused
by the use of unspecified materials, inadequate moisture
control, insufficient compactive effort, failure to fill
test holes properly, failure to adequately tie in repaired
and undisturbed liner sections, or construction during
periods of freezing temperature
Less-than-specified liner thickness or coverage from failure
to observe, monitor, and control soil placement and compaction
operations
Partings between liner lifts from failure to scarify and
control moisture in adjacent lifts
Leaks around designed liner penetrations resulting from
improper sealing and compaction
Erosion or desiccation of the liner from failure to provide
protective cover when construction is interrupted or after
liner completion.
2.3.4.3 Postconstruction--
Immediately before placement of any protective cover, the soil liner
should be inspected for cracks, holes, defects, or any other features that
may increase its field permeability. All defective areas should be removed.
If the underlying foundation is defective (soft or wet), then this material
also should be removed and the resultant volume should be replaced. Exca-
vated areas of the soil liner should be repaired by the method verified
during test fill construction; inspection should ensure that there is
continuity between the repaired and undisturbed areas. Special attention
should be paid to the final inspections of the sidewall and bottom slopes,
liner coverage, liner thickness, and the coverage and integrity of the
cover placed over the liner. The completed liner should be protected from
desiccation, erosion, and freezing immediately following completion of the
uppermost lift.
27
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2.3.5 Flexible Membrane Liners
The purpose of a flexible membrane liner (FML) in a hazardous waste
land disposal facility is to prevent the migration of any hazardous constit-
uents into the liner during the period that the facility is in operation
and during a 30-year postclosure monitoring period. In addition, FMLs
should be compatible with the waste liquid constituents that may contact
them and be of sufficient strength and thickness to withstand the forces
expected to be encountered during construction and operation.
This section describes the inspection activities necessary to ensure
that an FML will meet or exceed all design specifications. Specific tests
mentioned in this section are listed and referenced in Appendix A.
2.3.5.1 Preconstruction--
Preconstruction activities for FMLs include inspection of the raw
materials, manufacturing operations, fabrication operations, and final
product quality; observations related to transportation, handling, and
storage of the membrane; inspection of foundation preparation; and evalua-
tion of the personnel and equipment to be used to install the FML. These
activities are discussed in the following subsections.
2.3.5.1.1 FML manufacture—Quality assurance for FML manufacture
should begin with the testing of the polymer raw materials. The supplier
will generally provide documentation confirming that the raw materials
comply with the manufacturers' product properties and performance require-
ments. However, the manufacturer and the hazardous waste land disposal
facility CQA officer also should inspect the polymer raw materials. The
specific observations and tests that these individuals may make, depending
on the type of raw materials being supplied, include (adapted from Knipschild
et al., 1979):
Density. This property gives an indication of the material's
molecular structure and degree of crystallinity, which can
be related to mechanical properties such as strength and
deformation.
Melt Flow Index. The constancy of this property within
narrow tolerance ranges ensures consistent molecular weight
and rheological properties for high density polyethylene.
Knowledge of the value for this property is also helpful
when selecting production process parameters.
iffi
Relative Solute Viscosity For Hypalon . The value of this
property indicatesa polymer's mean molecular weight and its
degree of polymerization. These properties affect consistency
of processing and the finished product's physical properties.
®
Percent Volatile ComponentsFor Hypalon . This test gives a
value for the moisture content of the raw material. It is
important to control this factor to ensure that a product is
free from bubbles and pores.
28
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Percent Carbon Bjack. Constant control of the amount and
distribution of carbon black in the resin is important.to
ensure protection against UV radiation.
Additional tests of polymer raw materials may be required by the site-specific
CQA plan. These additional tests would be dependent upon the type of
polymer being supplied and the environment to which it will be subjected.
Standard Number 54 (NSF, 1983) and Koerner (1986) contain descriptions of
additional FML test methods.
Other types of raw materials that may be used in the production of
specific membrane types include additives and reinforcing materials. These
types of materials should be manufactured under the vendor's quality control/
quality assurance program and a certification indicating that they meet the
performance specifications should be provided. These additives should also
be inspected to confirm that they are the materials that were requested and
that they were packaged, labeled, and shipped as specified to prevent damage.
The compounding ingredients used in producing membrane liners should
be first quality, virgin material providing durable and effective formula-
tions for liner applications. Clean rework materials containing encapsulated
scrim or other fibrous materials should not be used in the manufacture of
FMLs. Clean rework materials of the same virgin ingredients generated from
the manufacturer's own production may be used by the same manufacturer,
provided that the finished products meet the product specifications.
Each manufacturer should have a manufacturing quality control program
based on the manufacturing method used and the type of membrane being
produced. The hazardous waste land disposal facility CQA officer should
obtain a copy of and review the manufacturer's quality control program.
This review should include a visit to the production plant for the purpose
of viewing quality control activities and laboratory testing facilities.
If there are areas where the CQA officer feels the manufacturer's quality
control program is weak, he may request that the manufacturer conduct
additional tests. The CQA officer may also conduct more tests to verify
the manufacturer's product specifications.
The completed FML also should be tested by the manufacturer and these
test results verified by the hazardous waste land disposal facility CQA
personnel. This phase of CQA is necessary to confirm that the final product
meets the liner performance specifications and to establish a "fingerprint"
that will be used to ensure that material delivered to the site is as
specified (Section 2.3.5.1.3). Examples of finished product specifications
that may be tested for various liner types include (Eorgan, 1985; VanderVoort,
1984):
Thickness
Tensile properties
29
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Tear resistance
Puncture resistance
Density
High temperature
Low temperature
Dimensional stability
Resistance to soil burial
Stress crack resistance
Oil absorption
Ozone resistance
Heat aging
Volatility loss
Percent carbon black
Ultraviolet (UV) resistance
Chemical resistance
Specific gravity
Percent swell
Ply adhesion
Scrim characteristics
Hardness.
Several of the more commonly used physical property test methods are listed
in Appendix A and Section 2.3.5.2 of this document as well as in Table VIII-1,
p. 407, of "Lining of Waste Impoundment and Disposal Facilities" (EPA,
1983) and in Standard Number 54 (NSF, 1983).
The FML manufacturer and CQA officer should retain a sample of the
finished liner from each raw material batch (identified by lot number) for
future reference. Appropriate documentation (e.g., product specifications,
lot number) should be included with each sample. If problems with the FML
occur, it would then be easy to trace the material to the specific batch.
When seam samples are retained, it is not necessary to retain a separate
FML sample from each of the batches.
2.3.5.1.2 FHL fabrication—Factory seaming before shipment to the
construction site is necessary for some FML types. Factory seams are used
to join smaller liner sections into larger panels or blankets, which will
then require fewer field seams. Blankets or panels are then assembled in
the field from roll goods according to the designer's or the installer's
field layout. Any changes in the layout of factory seams should be approved
by the designer and/or installer and the owner/operator. Personnel perform-
30
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ing the factory seaming should meet the same reqiurements as those perform-
ing the field seaming. The factory seam should be of equal or better
quality than that described in Section 2.3.5.2.2.
Factory seams should be 100 percent nondestructively tested using
recommended techniques before the FML is shipped from the fabrication plant
(Mitchell and Spanner, 1984). Rejected seams should be fully documented
and repaired. The CQA officer should review the fabricator's quality
control documentation to ensure that proper seaming procedures were followed
and the resulting FML seams are of the specified quality. After FML shipment,
the CQA officer also should inspect factory seams to ensure that the seam
overlap is as specified and that the proper seaming procedure was used.
The CQA officer should destructively test several factory seam samples per
blanket. In some cases, destructive testing of the blanket's seams may be
performed prior to its shipment to a site. It is recommended that this
testing be done by an independent laboratory with the quality control
documentation being sent directly to the site CQA officer for review. Any
necessary repairs to the blanket should be in accordance with approved
techniques, and the repaired areas should be nondestructively tested to
verify their integrity.
2.3.5.1.3 FML transportation and storage—FMLs are usually shipped in
rolls or folded on pallets. When rolls are used, CQA inspection personnel
should confirm that the FML has been protected with some type of covering
material*, often a thick sheet of the same material as the membrane is used.
When the membrane is folded on pallets, it should be placed in heavy cardboard
or wooden crates before its shipment. The roll or pallet of finished
materials should be marked to show the following minimum information (adapted
from Schmidt, 1983):
Name of manufacturer/fabricator
Product type
Product thickness
Manufacturing batch code
Date of manufacture
Physical dimensions (length and width)
Panel number or placement according to the design layout
pattern
Direction for unrolling or unfolding the membrane.
To ensure that the material that was approved in the chemical compati-
bility test is the material that was delivered to be installed, it should
be identified by an appropriate "fingerprint" (Morrison et al., 1982; Haxo,
1983; NSF, 1983). Samples should be obtained and tested from each shipment
31
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received at the job site. The shipment should be rejected if the product
is not consistent with what was originally approved.
The FML also should be inspected to confirm that it is not damaged and
to ensure that any damage is corrected. Damage may include:
Puncture from nails or splinters
Tears from operation of equipment or inadequate packaging
Exposure to temperature extremes resulting in unusable
material
Blocking; the bonding together of adjacent membrane layers,
which may be caused by excessive heat
Crumpling or tearing from inadequate packaging support.
These types of damage may be avoided by careful handling of the FML during
preparation for shipment and of the packaged crates and rolls of materials.
When damage to a crate or roll cover has occurred, careful examination
of the underlying material by CQA inspection personnel is required. If
damage is found, CQA inspection personnel should carefully examine the
entire shipment for damage.
Onsite storage of the synthetic membrane liner should be in a secure
area with provisions for shelter from adverse weather and should be as
brief as possible. This helps avoid damage caused by the following:
UV light
Heavy winds or precipitation
Temperature extremes [i.e., loss of plasticizers in polyvinyl
chloride (PVC), curing and adhesion of adjacent surfaces of
chlorosulfonated polyethylene, and creation of permanent
folds or wrinkles in certain liner types]
Vandals,
2.3.5.1,4 Lower bedding layer: placement—The observations and tests
necessary to ensure that an adequate FML lower bedding layer Is provided
are discussed in Section 2.3.2.2. Prior to FML placement, it is extremely
important to *nspect visually the bedding layer surface to confirm that it
is free from clods of soil, rocks, roots, sudden or sharp changes of grade,
and standing water. CQA inspection personnel also should confirm that the
soil has been sterilized when necessary with an approved herbicide using
the manufacturers' recommended procedures.
32
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In composite liner systems, the lower FML bedding is the compacted
low-permeability soil liner. If the bedding is subject to drying and
cracking, precautions should be taken by the facility owner/operator to
prevent desiccation. This prevention may be in the form of a temporary
liner (e.g., thin plastic cover) or special nonreactive chemicals. If a
temporary liner is used, the CQA officer should ensure that it is secure at
the edges and that, before the installation of the designed FML, the tempo-
rary liner is removed and any soil liner cracks are documented and repaired.
If desiccation cracks are observed, the appropriate techniques and specifi-
cations for correction should be provided in the design specifications.
2.3.5.2 Construction--
Failure of an FML can result from defective manufacturing and fabrica-
tion, improper handling and storage, or poor installation methods. The
observations and tests necessary to detect these defects during construc-
tion are discussed in the following subsections.
2.3.5.2.1 FML placement—Inspection activities that are necessary and
should be documented during liner placement include (adapted from Kastman,
1984):
Checking delivery tickets and synthetic membrane manufacturers'
quality control documentation to verify that the synthetic
membrane rolls received onsite meet the project specifications.
[In addition, "it is usually good practice to take the
identifying labels from each roll or pallet and save them
for future reference. Further, the position of each roll or
pallet of material should be noted on a final installation
drawing. This document can be used as future reference
should problems occur" (Schmidt, 1983)]. As an additional
check to ensure the quality of the product being delivered,
a sample should be taken, "fingerprinted," and that fingerprint
should be compared with the fingerprint of the product
originally contracted for. If these fingerprints are different,
the material should be rejected.
Observations to ensure that the FML placement plan was
followed.
Observations of the weather conditions (i.e., temperature,
humidity, precipitation, and wind) to ensure that they are
acceptable for membrane placement and seaming.
Observations and measurements of the anchor trench to ensure
that it is as specified in the design drawings. If the
trench is excavated in soil that is susceptible to desiccation,
only that trench length that is required for 1 day's work
should be excavated. Consideration should be given to using
a temporary liner in the trench to prevent desiccation.
Trench corners should be rounded to prevent stressing the
membrane. Good housekeeping practices should be used in the
33
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trenching operation by not allowing any loose soil material
in the trench or on the downhill side of the trench. Back-
filling of the trench should be performed as soon as possible
and compacted with care so as not to damage the FML.
Observations and tests to confirm that all designed liner
penetrations and liner connections are installed as specified.
Liner penetrations should be verified for appropriate clamp
and caulking use, for appropriate material, for good seaming,
and for good housekeeping practices. No sharp bends on
foundations (concrete pads) should be allowed. Soil compac-
tion adjacent to concrete pads should be performed as speci-
fied to prevent differential settlement.
Measurements to confirm that required overlaps of adjacent
membrane sheets were achieved, that proper temporary anchorage
was used (e.g., sand bags or tires), that specified temporary
and final seaming materials/techniques were used, and that
the blanket was placed in a relaxed (nonstressed) state.
As each synthetic membrane panel is placed, it should be visually
inspected for tears, punctures, and thin spots. To accomplish this, the
panels should be traversed by CQA inspection personnel in such a way that
the entire surface, including all factory seams, is inspected. For synthetic
membranes that are fabricated from roll stock widths of about 5 feet, the
normal procedure used to detect membrane defects is to walk along each roll
stock width and inspect the entire length of the sheet. Any defects should
be marked on the synthetic membrane for repair.
The overall quality of a flexible membrane liner installation can be
affected by the weather conditions during which it was installed. CQA
inspection personnel should be aware of all of these factors and the effects
they may have on the specific membrane type and seaming procedure being
used. If the weather becomes unacceptable for installation of the liner,
the CQA officer should recommend stopping the membrane installation until
conditions again become favorable, thus minimizing the potential for unaccept-
able installation.
Inspection activities during FML placement will help ensure that the
completed facility meets or exceeds the design specifications by preventing
or detecting the following;
Liner damage from adverse weather conditions, inadequate
temporary anchoring, or rough handling
Improper liner placement (if the placement plan is not
followed) and, as a result, inadequate coverage with the
available materials or an excess number of field seams
results
34
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Inadequate sheet overlap, possibly resulting in poor quality
seams
Nonwelded or nonseamed sections
Inadequate seam strength.
2.3.5.2,2 FML seaming—Inspection activities that should be documented
during field seaming operations include:
Observations to ensure that the membrane is free from dirt,
dust, and moisture
Observations to ensure that the seaming materials and equip-
ment are as specified.
Observations and tests to ensure that a firm foundation is
available for seaming
Observations of weather conditions (e.g., temperature,
humidity, wind) to ensure that they are acceptable for
seaming
Measurements of temperatures, pressures, and speed of seaming,
when applicable, to ensure that they are as specified (e.g.,
gages and dials should be checked and readings recorded)
Measurements of the curing time between seaming and seam
testing to ensure that it is as specified (when applicable)
Observations to ensure that the membrane is not damaged by
equipment or personnel during the seaming process.
Inspection activities help ensure that the completed facility meets or
exceeds the specified design by preventing and detecting the following:
Seam gaps or weak spots resulting from the presence of dirt
or dust
Less-than-specified seam strength resulting from the use of
unspecified materials, improperly operating equipment,
insufficient pressure, ambient temperature extremes, or
insufficient dwell time
Liner damage caused by cleaning or bonding solvents and
seaming equipment. Liner damage may also result from walking
on the membrane while wearing improper footwear or from the
improper disposal of cigarette butts.
After field seams are installed, they should be inspected to ensure
that a homogeneous bond was formed. Different nondestructive inspection
35
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methods (in addition to visual observations) are available for testing
seams in the field, depending on the type of liner material being placed
(Mitchell and Spanner, 1984):
Nondestructive tests should be performed on 100 percent of
the field seams. Failed seams should be recorded as to
location and seaming crew. The data should be reviewed for
possible patterns. Repairs should be made in accordance
with approved techniques and retested to verify their integ-
rity.
Destructive seam testing should be performed at locations
and frequencies as selected by the CQA inspection personnel.
A minimum number and location per seam length per seam crew
should be established. If different seaming techniques are
used, additional tests per seaming type should be added.
Additional test locations may be necessary at the CQA officer's
discretion. These locations may be based on suspicion of
contamination by dirt or moisture, change in seaming materials,
increase in failed nondestructive tests, and other causes
that could result in unacceptable seams.
Destructive seam samples should be large enough for the
installer to check in the laboratory, for an independent
laboratory evaluation, and for site owner archiving. If
possible, the seam should be destructively tested in the
field at the time of sampling (provided sufficient time has
elasped for the seam to cure properly). Proper documentation
should follow each seam sample as to location, time, crew,
and technique.
Laboratory testing should be performed in accordance with
design specifications with predetermined pass/fail values.
Both peel and shear testing should be performed as suggested
by Standard Number 54 (NSF, 1983) or ASTM, for the specific
material type.
For field seams that fail, the seam can either be reconstructed
between the failed and any previous passed seam location or
the installer can go on either side of the failed seam
location (10-foot minimum), take another sample, test it and
if it passes, reconstruct the seam between the two locations.
If it fails, the process should be continued. In all cases
acceptable seams must be bounded by two passed test locations.
All repairs should be performed as soon as possible and in
accordance with the design specifications. Each repair
should be nondestructively tested for continuity. Documenta-
tion of all repairs including location, type, and method
used should be made.
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2.3.5.2.3 Anchors and seals installation—When a hazardous waste land
disposal unit design calls for penetrations (e.g., structures and pipes) in
the flexible membrane liner, CQA inspection personnel must ensure that the
seals around such penetrations are of sufficient strength and are impermeable
to leachate. Specific Inspections that should be made on all seals or
anchors include:
Observations to ensure that the materials (i.e., pipe boots
and sealing compounds) are compatible with the waste and are
as specified
Observations and tests to ensure that the sealing systems
(i.e., pipe boots) were installed as specified (are leak
free) and in the proper locations
Observations to ensure that all objects that may be placed
adjacent to the synthetic membrane (i.e., batten bars, soil
in an anchor trench, and concrete structures) are smooth and
free of objects or conditions that may damage the membrane
Observations and tests to ensure that all seals and anchors
are complete (i.e., no gaps or areas of uncompacted backfill).
Inspection activities during this phase of construction will ensure
that the completed facility meets or exceeds all design specifications by
preventing or detecting the following:
Compatibility or corrosion problems from the use of unspeci-
fied materials
Leaks around penetrations or slipping of the membrane from
incomplete seals or inadequate compaction of backfill
Flexible membrane damage from rough edges, sharp corners, or
rocks. Membrane damage can also occur from excessive stress
placed on the liner because of improper location of sealing
and/or anchoring mechanisms.
2.3.5.2.4 Upper beddinglayer placement—An upper bedding layer,
often referred to as a protective cover, when required over an FML, should
be placed as soon as possible after installation to protect the FML from
weather conditions, equipment, and vandalism. The covering of the FML,
while important and necessary, should not be performed until the FML Instal-
lation is completed and accepted. However, on very large jobs, it may be
necessary to accept and cover portions of the liner prior to completion of
the entire liner.
Upon completion of flexible membrane liner installation and seam
testing, but prior to placement of the upper bedding layer, the liner
should undergo a thorough visual inspection for any damage that may have
occurred during installation. If any damaged areas are located, they
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should be marked and patched using approved repair methods. These patched
areas should be nondestructively tested to ensure that they do not leak.
The protective cover is usually soil that is free of rocks, sticks,
and other items that could damage the membrane. Inspection activities that
should be conducted during protective cover installation include:
Observations and tests to ensure that the cover material
meets specifications
Observations to ensure that the cover material is free from
objects that could damage the liner
Observations to ensure that the equipment used to place the
cover material does not operate directly on the FML and does
not puncture or tear the FML
Measurements to ensure that the entire liner is covered with
the specified thickness of cover material.
There are a few standard checks and test methods that can be used, in
addition to visual observations, to ensure that a flexible membrane liner's
protective cover is installed according to the specified design. These
checks include surveying using conventional or laser/electronic instruments
to ensure that the layer thickness is as specified. The thickness of the
cover layer can also be monitored simply by measuring it with a marked
measuring staff. When this method is used, CQA inspection personnel must
ensure that the staff does not puncture the underlying liner. The bedding
layer soil type may be inspected by using visual-manual soil identification
techniques and index property tests. These test procedures are briefly
discussed in Section 2.3.4.1.1 and are listed and referenced in Appendix A.
Inspection activities during upper bedding layer placement will help
ensure that the following problems will be prevented or detected:
Liner damage from the use of unspecified materials, equipment
or human traffic, or weather conditions
Insufficient upper bedding layer thickness or coverage.
2.3.5.3 Pos tconstructi on—
To check for leaks in the installed membrane liners of small landfills
or surface impoundments, the facility can be filled or partially filled
with water and seepage from the site measured after accounting for evapora-
tion. This method is often combined with leachate collection system (LCS)
testing and, when feasible, is the best way to ensure that the synthetic
liner will function according to specifications after it is put into service,
assuming that no waste/liner compatibility problems occur. In the case of
double liner systems, this type of testing will be more complex because of
the presence of two LCSs.
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If the waste facility shows evidence of leakage after filling with
water, the leak(s) must be located, repaired, and the FML retested before
it can be accepted. Several techniques, including tracer dyes and electri-
cal resistivity, may help to locate the leak(s),
2,3.6 Leachate Collection Systems
The purpose of a primary LCS in a landfill is to minimize the leachate
head on the top liner during operation and to remove liquids from the
landfill through the postclosure monitoring period. The LCS should be
capable of maintaining a leachate head of less than 30 cm (1 foot). The
purpose of a secondary LCS (sometimes referred to as a leak detection
system) between the two liners of a landfill or surface impoundment is to
rapidly detect, collect, and remove liquids entering the system through the
postclosure monitoring period.
The following sections describe the inspection activities that are
necessary to ensure that a completed LCS is constructed to meet or exceed
the specified design. In this document, the individual parts that make up
an LCS are referred to as subcomponents. Specific tests referred to in the
following sections are listed and referenced in Appendix A.
2.3.6.1 Reconstruction—
Preconstruction activities for an LCS include inspection of all materials
and examination of the LCS foundation.
2.3.6.1.1 Material inspection—Observing all LCS subcomponent materials
as they are delivered to the site is necessary to confirm and document that
these materials conform to the design criteria, plans, and specifications.
To accomplish this, inspection activities should include the following:
Observations to ensure that all synthetic drainage layers
and/or synthetic filter layers meet the design specifications.
Observations and measurements to ensure that the pipes are
of the specified size and strength, are constructed of the
specified material, and that pipe perforations are sized and
spaced as specified.
Observations and tests to ensure that the soils to be used
in the LCS are of the proper size and gradation, do not
contain unspecified types of materials, and that specified
provisions to keep LCS soils clean during storage, handling,
and placement are followed.
Observations to ensure that all prefabricated structures
(e.g., manholes and sumps) are as specified in the design.
This should include inspection of any corrosion-resistant
coatings to confirm that they are present and without flaws.
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Observations of all mechanical, electrical, and monitoring
equipment to ensure that it is as specified in the design.
In some cases (e.g., pumps), the specific pieces of equipment
can be tested to ensure that they are operational.
Observations and tests to ensure that, when cast-in-place
concrete structures are to be installed, the raw materials
supplied and necessary forms are as specified in the design.
2.3.6.1.2 Foundationpreparation—An examination of the foundation
for the LCS should be performed before construction. In the case of double
liner systems, the bedding for both primary and secondary LCSs will be an
FML or a low-permeability soil liner depending on the type of facility.
Inspection activities should include:
Measurement of the horizontal and vertical alignment of the
foundation to ensure that leachate will flow toward the sump
Observation of the foundation to ensure that it is free of
debris and liquids that would tend to interfere with construc-
tion of the LCS.
2.3.6.2 Construction--
An LCS is composed of many separate subcomponents. Each of these
subcomponents must be installed as specified in the design to ensure proper
component function. The following subsections include discussions of
observations and tests that should be performed for each LCS subcomponent.
2.3.6.2.1 Bedding layer placement—To avoid damage to the foundation
of the LCS, a bedding layer may be placed before pipe network installation.
The bedding layer may be either a granular or manufactured material (i.e.,
geotextile). Inspection activities that should be performed include:
Observation of the bedding material to ensure that it is as
specified and that it does not contain objects that would
damage or alter the underlying foundation
Measurement of the thickness of the bedding layer to ensure
uniformity of layer depth
Observation of the area! coverage of the bedding layer to
ensure that it is the same as that specified in the design.
When manufactured materials are used, it should be verified
that sheets are joined or connected as specified in the
design.
These observations and tests are necessary to ensure that the materials in
the bedding layer do not damage the foundation.
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2.3.6.2.2 Pipe network Installation—The pipe network should be
placed according to the specified design. Inspection activities that
should be performed during pipe placement and joining include:
Observations and measurements to ensure that the pipes are
placed at specified locations and in specified configurations
Observations and tests to ensure that pipe grades are as
specified
Observations and tests to ensure that all pipes are joined
together as specified
Observations to ensure that the placement of any filter
materials around the pipe proceeds as specified in the
design
Observations and tests to ensure that backfilling and compac-
tion are completed as specified in the design and that, in
the process, the pipe network is not damaged.
Adequate CQA during this phase of LCS construction will prevent or detect
the following:
Clogging of the LCS pipes or sections of the pipes from the
improper installation of filter materials or from soil-laden
site runoff
Inadequate LCS function from the improper joining of pipes,
from the improper placement of pipes, or from mechanical
damage to the pipe network.
If the pipes are not adequately protected from fine particle accumu-
lations during the construction phase, it may be necessary to flush the
pipe network upon completion to remove sedimentation and debris and to
verify that the pipes are open. Standard sewer cleaning equipment can be
used to remove objects and debris remaining after simple flushing. If this
equipment is unable to pass through the line, it may mean that a section of
pipe has been crushed or displaced.
Testing of solid pressure and nonpressure LCS pipes should also be
conducted to check for leaks and the structural integrity of the solid pipe
network. No standardized test procedures are available to perform the test
for nonpressure pipes. The American Water Works Association has developed
a method for testing solid pressure pipes (AWWA, 1982).
In some cases, it may be desirable to look at the interior of the pipe
to verify its alignment and to confirm that there are no obstructions or
debris in the pipe. The procedure consists of pulling a television camera
mounted on skids through the pipe and recording the distance from the
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sta-ting point as the camera moves. The location of any problem can be
found by measuring the distance from the starting point. In the case of
the pipe used to transport leachate out of the facility, this procedure can
be used to identify sources of infiltration.
2.3.6.2.3 Drainage layer placement—
Granular drai nage1ayers—Granular LCS drainage layers are constructed
of clean, inorganic, free-draining, granular soils such as sand and gravel.
These soils are selected before their use in the LCS on the basis of their
grain size distribution.
Some or all of the soil drainage layer may be placed before or after
pipe placement. To ensure the quality of this drainage layer, CQA inspection
personnel should:
Test the soil to ensure that it is of the specified particle
size and free from excessive amounts of fines or organic
materials
Heasure the thickness and observe coverage of each drainage
layer lift as it is placed in the LCS
Observe the compaction process and test the compacted layer
to ensure its adequacy
Survey the completed layer to ensure that specified slopes
are obtained
Observe that the transport of fines by runoff into the LCS
is prevented by barriers or filters.
When pipe placement precedes granular soil placement, it is also necessary
to monitor soil placement and compaction operations to ensure that the LCS
pipes (and the FML) are not damaged or moved by the installation equipment.
CQA inspections during granular drainage layer placement will help
ensure the integrity of the facility by preventing or detecting the following;
Areas of lower than specified drainage layer permeability
resulting from the use of unspecified materials or from
fines that enter and clog the system
Less-than-specified layer thickness or coverage
Damaged and misaligned pipes
Damage to an underlying FML.
There are several standardized test methods that may be used to monitor
the drainage layer materials, placement, and compaction. The material type
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should be monitored using the methods discussed in Section 2.3.6.1.1. A
method for determining the permeability of the installed drainage layer,
along with the previously mentioned test methods, is listed and referenced
in Appendix A.
Syntheticdrainage layers—There are three main types of synthetic
drainage materials available for use in LCSs: nets, mats, and geotextile
fabrics. These synthetic drainage materials may be used alone or in combina-
tion with granular drainage layers to form the LCS for a hazardous waste
land disposal facility. For more information on synthetic drainage layer
design and construction, see GCA Corp. and E. C. Jordan Co. (1984).
Prior to the placement of geotextiles or synthetic drainage materials,
CQA inspection personnel should confirm that these materials are as speci-
fied and have not been damaged due to shipping or improper storage. Sev-
eral standardized tests are available to evaluate specified properties of
geotextiles. These include tensile strength, puncture or burst resistance,
tear resistance, flexibility, outdoor weatherability, and short-term chemical
resistance. For more information on these test methods, including discussions
on their applicability, limitations, and proper interpretations, the reader
is referred to Horz (1984). Appendix 6 of Horz (1984) also contains detailed
test procedures for fabric permeability and percent open area. There are
currently no published standard test methods for either of these properties.
CQA inspection personnel also should verify that the surface on which the
synthetic drainage layer or geotextile is to be placed has been prepared
properly. This may include surveying the slope or grade, inspecting material
type and compaction for soils, or inspecting flexible membrane seaming and
anchoring.
During the installation of a synthetic drainage layer or a geotextile,
the CQA inspection personnel should perform the following inspection activi-
ties:
Observations to ensure that the materials are placed according
to the placement plan
Measurements to ensure that the specified material overlap
is achieved
Observations to ensure that the material is free from wrinkles
and folds
Observations and tests, when required, to ensure that seams
are made according to the design specifications
Observations to ensure that weather conditions are appropriate
for placement and that the exposure of the synthetic drainage
layers or geotextiles to rain and/or direct sunlight during
and after installation is minimized
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Observations to ensure that the material is not damaged
during the installation process
Observations to ensure that barriers or filters are installed
to prevent clogging of drainage layers from soil-laden site
runoff.
Inspection activities during synthetic drainage layer placement will help
ensure that the completed facility meets or exceeds the design specifications
by preventing or detecting the following:
Geotextile or synthetic drainage layer slippage resulting
from improper placement or seaming
Stress damage to the material from improper placement
Improper material function because of wrinkles in the material,
inadequate seam overlap, improperly made seams, clogging of
the material by fine particles, or damage to the material
from weather conditions, human traffic, or equipment.
2.3.6.2.4 Filter layer placement—The filter layer subcomponents of
an LCS may be constructed of granular soils or synthetic materials. In
both cases the materials used in the filter layer are selected before
construction as part of the facility design.
Soil filter layers--LCS soil filter layer placement quality is checked
in much the same way as that for granular drainage layers; observations and
tests that should be performed and recorded include:
Soil tests to ensure that it is of the specified grain size
and free of excessive amounts of fines or organic materials
Observations of the placement process to ensure that it is
performed as specified
Measurements of the thickness of the filter layer to ensure
that it is as specified.
These observations and tests are necessary to ensure that areas of the LCS
do not become blinded or clogged by fine particles infiltrating the system.
If this occurs, the LCS will not function properly, and leachate levels in
the facility may exceed regulatory requirements.
Syntheti c f1 Her 1ayers--Geotexti1es are synthetic products specifically
designed to have high permeability and strength characteristics. Geotextile
filter layers will retain solid material while allowing liquids to flow
into the drainage layer and collection pipes. In this application, the
geotextile protects the drainage layer and pipe system from becoming clogged.
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Inspection activities that should be conducted during the placement of
a geotextile filter layer include:
Observations of geotextile placement to ensure that the
specifications are followed, including coverage of all
specified areas and adequate material overlap or seaming
Observations to ensure that the completed geotextile filter
layer or any other system subcomponent is not damaged during
placement.
These observations and tests are necessary to ensure that the LCS does not
become clogged.
2.3.6.2.5 Sumps and associated structureJnstaVlatlon—Sumps and
manholes can be manufactured offsite and delivered to the site ready for
installation as part of the LCS. The design engineer will usually specify
that, at a minimum, the supplier should furnish certification with appro-
priate documentation that the structures have been fabricated according to
the design engineer's specifications. Additional inspection of precast
concrete, steel, and fiberglass structures may be needed to confirm the
identity and quality of manufactured structures. Inspection activities
that should be performed include;
Observations to ensure that the structures were not damaged
during shipment
Measurements to ensure that the structures are of the speci-
fied dimensions and capacity
Observations to ensure that the structures are made of the
specified materials
Observations to ensure that any corrosion-inhibiting coatings
are free from defects such as flaking, scratches, or blisters.
If defects are present, manufacturers' specifications for
repair should be available.
These observations and tests are necessary to ensure that LCS structures
are constructed of specified materials, are of adequate size, and are not
damaged. If any of these situations occur, the LCS may not function properly.
Visual observations of manhole and collection tank installation are
necessary to ensure that the components are installed as specified in the
design and that they are not damaged during the process. Installation of
the footings or foundations for these structures also should be observed to
ensure that damage to the liner is prevented. Surveying should be performed
to confirm that all structures are installed in the proper locations.
In the event that manufactured structures are not appropriate, cast-
in-place concrete structures may be constructed. The installation of
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concrete structures, such as manholes and collection tanks, requires visual
inspection of the installation, including cast-in-place procedures, and
tests of the concrete that is cast at the LCS site. Observations that
should be made include:
Inspection of formwork to ensure that it is complete and has
the specified dimensions
Inspection of concrete placement operations
Inspection of the curing process to ensure that a satisfactory
moisture content and favorable temperature are maintained.
These inspection activities are necessary to ensure that the resulting
structure is of the specified size and strength.
Design specifications for concrete will usually require testing of the
type, quality, and gradation of the aggregates; the consistency and air
content of fresh concrete; and specimens of the concrete for strength.
Grain size distribution tests and visual-manual classification are usually
required for the aggregates before their use. Consistency, or slump, of
the concrete should be determined to ensure that it conforms with the
design specifications. The air content of the freshly mixed concrete can
be determined by the pressure method. The compressive strength of samples
of concrete can be determined using the strength test.
2.3.6.2.6 Mechanical and electrical equipment instal1ation--Instana-
tion of mechanical and electrical equipment such as pumps, valves, motors,
liquid-level monitors, and flowmeters is usually the final activity during
LCS construction. The CQA inspections that should be performed include:
Observations of all mechanical and electrical equipment
installation to ensure that it is in accordance with the
design specifications and manufacturers' recommendations
Testing of all mechanical and electrical equipment in accord-
ance with manufacturers' instructions and operations manuals.
Authorized service representatives of the manufacturers may
be present to provide any necessary assistance.
These observations and tests are necessary to ensure that the facility
meets or exceeds all design specifications. This will reduce the possibility
of equipment failure and leachate head buildup in the LCS.
Inspection of electrical connections for mechanical equipment should
be performed by personnel certified by national and/or State licensing
agencies to perform electrical work. The visual observations necessary for
electrical equipment are the same as those previously discussed for me-
chanical and monitoring equipment. CQA testing should focus on four major
areas: insulation, grounding, equipment, and control circuits.
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2.3.6.3 Postconstruction—
Postconstruction inspection of an LCS should include:
Observations to ensure that all system subcomponents have
been installed in the proper locations and according to
design and manufacturers' specifications
Testing to ensure that all pumps operate and that all elec-
trical controls and monitoring equipment perform in accordance
with the specified design.
A final performance test for the primary LCS may be included as part
of a facility's CQA plan. This test may be conducted by filling all or a
portion of the system with a known quantity of water. The water should
then be removed from the system and its volume determined. The volume of
water remaining is the system's storage volume. If the storage volume is
significantly higher than expected, there may be areas of the system that
are not draining properly. If this is the case, the entire primary LCS
should be inspected to locate the areas that are not draining properly.
Where performance testing such as this is difficult, alternative inspection
activities are presented in Bass (1986), Corrective measures should then
be implemented to ensure that the specified drainage can be obtained.
A final performance test of this type should not be conducted on the
secondary LCS as this system must remain dry to enable detection of leaks
through the primary liner.
2.3.7 Final Coyer Systems
Final cover systems for hazardous waste land disposal facilities are
designed to provide long-term minimization of liquid migration and leachate
formation in the closed landfill by preventing the infiltration of surface
water into the facility for many years and minimizing it thereafter in the
absence of damage. Final cover systems also control the venting of gas
generated in the facility and isolate the wastes from the surface environment.
Final cover systems are constructed in layers, the most important of which
are the barrier layers. Other layers are included to protect or to enhance
the performance of the barrier layers. A final cover system must be construc-
ted so that it functions with minimum maintenance, promotes drainage and
minimizes erosion or abrasion of the cover, accommodates settlement and
subsidence so that the cover's integrity is maintained, and has a permeability
less than or equal to the permeability of the bottom liner system component
with the lowest permeability. In this document, the cover system layers
are referred to as subcomponents.
The following subsections describe the quality assurance activities
necessary to ensure that a completed final cover system meets of exceeds
all design specifications. Specific tests mentioned in this section are
listed and referenced in Appendix A.
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2,3.7.1 Reconstruction—
Reconstruction activities for final cover systems include screening
incoming materials for the system subcomponents and compacting test fills
for the soil barriers. These and other preconstruction activities for each
cover system subcomponent are identified below and described in the following
sections:
Low-permeability soil barrier (Section 2.3.4.1)
Flexible membrane barrier (Section 2.3.5.1)
Drainage and venting layers (Section 2.3.6.1).
For the topsoil and vegetation subcomponents, it should be verified
that sufficient quantities of topsoil, fertilizer, soil conditioners, and
seeds are available to complete the topsoil/vegetation cover, and that the
quality of these materials is as specified in the design. Topsoil should
be characterized for the required agronomic properties (Gilman et a!.,
1983).
Before facility closure, it may be desirable to plant experimental
plots to verify that the proposed vegetation will be tolerant of the expected
conditions in the final cover system. Conditions that should be considered
include local climate as well as (Gilman et a!., 1983):
Cover soil type, depth, and compaction
Waste depth, type, age, and compaction
Surface slope.
2.3.7.2 Construction—
The inspection activities necessary for evaluating the construction
quality of the final cover system component are addressed below by subcompo-
nent, beginning with the final cover foundation layer. Many of the activi-
ties are the same as for other facility components addressed earlier; e.g.,
the low-permeability barrier is much the same as the low-permeability soil
liner. Inspection activities are referenced to earlier sections as approp-
riate.
For all cover system subcomponents, CQA personnel should be especially
attentive to construction around standpipes, vent pipes, and the perimeter
of the compacted fill area. Design requirements may be more restrictive in
these areas. In the perimeter area, the cover subcomponents must join the
liner subcomponents through a relatively complex design. The CQA officer
should be especially cognizant of the perimeter design requirements and the
measurements necessary to ensure that these requirements are met.
2.3.7.2.1 Final cover system foundation preparation—Before the
construction of the cover foundation layer or overlying cover subcomponents,
observation and tests should include an evaluation of the stability of the
cover system foundation. This is necessary to minimize the potential for
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future differential settlement or subsidence and resultant final cover
system damage.
Soil materials to be used in the cover system foundation should be
observed and tested as necessary to confirm that they meet the specified
design. Materials specifications may include a maximum particle size and a
requirement that they be free of large objects that could damage or make
the placement of the overlying low-permeability soil barrier difficult.
The construction materials of any subcomponents that are to be installed
with their bases in waste or in the foundation layer (e.g., gas vents)
should be inspected for conformance to design specifications.
The cover system foundation should be inspected to ensure that its
thickness, coverage, surface slope, density, and bearing strength are as
specified in the design.
2.3.7.2.2 Low-permeability soil barrier placement—The low-permeability
soil barrier provides a base for the flexible membrane barrier subcomponent
of the final cover system and provides long-term minimization of liquid
infiltration. It serves as a secondary barrier to infiltration in case the
flexible membrane barrier fails.
Before construction of the low-permeability soil barrier subcomponent
of the cover system, soil materials should be tested to ensure that they
are as specified in the design. Throughout the construction process,
testing of incoming soil materials should be done on a per-unit-volume
basis, and more frequently when CQA inspection personnel suspect a change
in soil properties.
The low-permeability soil barrier is constructed much like the low
-permeability soil liner. However, the cover system foundation may have a
lower bearing strength than the soil liner foundation, and this may necessi-
tate using different equipment or methodology than that which was used to
construct the soil liner. This may necessitate the construction of a test
fill utilizing the same materials, equipment, and procedures to be used for
constructing the soil barrier to ensure that the required permeabilities
can actually be achieved in the field and to determine the relationship
between soil density, moisture content, compactive effort, and permeability
achieved in the test fill (see Section 2.3.4.1.2). This same relationship
then must be obtained during the construction of the low-permeability soil
barrier subcomponent. As with compacted low-permeability soil liners, it
is necessary to monitor soil type, moisture content, density, compactive
effort, lift thickness, clod size, uniformity of compaction, completeness
of coverage, and permeability during construction. A more complete discus-
sion of inspection activities for low-permeability soil liners can be found
in Section 2.3.4.
Seals around penetrations such as gas vent pipes and LCS standpipes
should be tested to ensure that they do not leak. Compaction of the soil
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around penetrations should be closely observed, and clod size, especially
where soil is compacted using hand compactors, must be carefully controlled,
It is especially important to inspect the perimeter of the cover, where the
low-permeability soil barrier subcomponent joins or overlies the liner
system, to ensure that it is installed to conform to the specified design.
After completion of the low-permeability soil barrier subcomponent,
the surface slope of the barrier layer should be surveyed to ensure that it
is constructed as designed and that no depressions remain into which water
will flow and stand. In addition, the soil layer should be inspected to
ensure that it provides a suitable base for the overlying flexible membrane
barrier.
2.3.7.2.3 Flexible membrane barrier i nstal1ation—The flexible membrane
barrier prevents infiltration of precipitation through the cover and into
the underlying waste.
Before installation of the flexible membrane barrier, the membrane
materials should be observed and tested to ensure that they are as specified
(see Section 2.3.5.1). Field seaming equipment and materials should be
examined to ensure that they are as specified in the design and are adequate
to do the job. Any other materials, such as hardware for anchoring and
sealing the membrane to penetrating objects, should be checked for adherence
to design specifications.
The base for the flexible membrane barrier subcomponent (the low-permea-
bility soil barrier subcomponent) should be inspected before membrane
installation to ensure that its surface is as smooth as possible and that
there are no objects that might damage or penetrate the membrane.
All observations and tests used for FML installation are pertinent to
the installation of the flexible membrane barrier final cover system sub-
component. A discussion of inspection activities for flexible membrane
liners is presented in Section 2.3.5. CQA personnel should be especially
attentive to the vent and standpipe penetrations to ensure the integrity of
the connections bonding them to the membrane. Around the perimeter of the
final cover system, where it joins the liner system, the installed flexible
membrane barrier should be tested to ensure that it is installed to conform
to the specified design because this is an area with a relatively high
potential for leakage.
2.3.7.2.4 Bedding layer placement—An upper bedding layer may be
placed to act as a protective buffer between the flexible membrane barrier
subcomponent and the overlying drainage layer. This layer acts to protect
the membrane from possible puncture by coarse drainage system materials.
Bedding layers may be either a granular material or a synthetic material
such as a geotextile. Specific observations and tests to be performed are
listed in Section 2.3.5.2.4.
Perhaps the most critical inspection activity during the placement of
a bedding layer on top of a flexible membrane is to observe the placement
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process closely to ensure that the construction equipment does not damage
the membrane. Following installation, the surface slope of the bedding
layer should be surveyed to ensure that the design slope is achieved.
2.3.7.2.5 Drainage and gasventing layer placement--The drainage
layers in a final cover system are designed to conduct away infiltrating
precipitation before it can penetrate the barrier layers and to vent gas
from the facility to appropriate treatment or collection facilities. The
gas discharge layer has a consistency and configuration similar to that of
the water drainage layer. Both layer types function to transmit fluid
preferentially. The main distinction between them is their position in the
cover system. The gas discharge layer is placed below the flexible membrane
and low-permeability soil barriers and intercepts gases rising from waste
cells and directs them to controlled gas discharge vents. The water drainage
layer is located above the barriers to intercept and drain water percolating
from the surface and direct it to the runoff control system. Both the gas
venting and water drainage layers in a final cover system are similar in
design and construction to the LCS and may be composed of granular soils
and/or synthetic drainage layers, including geotextiles. See Section
2.3.6.2.3 for a more detailed description of drainage layers.
Current regulations require controlled discharge (collection and/or
treatment) of hazardous or nuisance gases from facilities. Controlled
discharge of gases accumulating in the facility is necessary because of the
potential harm that toxic, combustible, and/or malodorous gas may have on
human health and the environment. The gas may be collected at the discharge
point and transported for treatment or incineration. Alternatively, devices
for removing harmful components from the gas or incinerating the harmful
components in place may be devised and installed at gas discharge points.
This document does not cover these devices in further detail, as currently
there is no guidance for designing or constructing them.
The materials used in the construction of the drainage or venting
layer are likely to have restrictive specifications, whether materials are
soil or synthetic materials. Preconstruction activities must include an
inspection of those materials to make certain that they meet the design
specifications. The inspection should continue through the construction
period as long as materials continue to be delivered to the site. Other
preconstruction activities include inspection of the base for the drainage
or gas venting layer to ensure that it is and remains in the condition that
was specified in the design. Any protrusions, such as vents and standpipes,
should also be inspected for any deviations from design specifications.
The inspection procedures during the construction of the drainage and
gas venting layers are much the same as those used in the construction of
the LCS at the bottom of the landfill. Those procedures are addressed in
detail in Section 2.3.6.2. Inspection activities will include ensuring
that the specified thickness and surface slope are achieved and that particle
size and permeability are as specified in the design. Observations should
be made of the filling process around vents and standpipes to prevent
damage or misalignment of those structures.
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Inspection of the installation of the drainage layers around the
perimeter of the cover system is particularly important, for it is here
that the system connects to the surface drainage facilities. It is espe-
cially important to ensure that the design specifications, particularly
dimensions and slopes, are achieved. In addition, controlled gas discharge
or collection systems should be checked for proper installation and function.
2.3.7.2.6 Filter layer placement—The purpose of a filter layer above
(or below) a drainage layer is to stop the migration or piping of fine
materials that could plug a drainage layer and render it ineffective. The
filter layer can be constructed of soil materials or may be a geotextile.
Soil layer specifications include particle size range and dry density.
Geotextiles may be specified according to apparent opening size.
Inspection activities prior to the construction or installation of the
filter layer include inspection of the filter materials to confirm that
they meet the design specifications.
During the construction of the filter layer, inspection activities
should include monitoring of the particle size (for soil materials) or
geotextile type and certification, uniformity of thickness for soil, seaming
or overlap for geotextiles, slope of the surface, and coverage (particularly
around the perimeter of the cover system). CQA inspection personnel should
be particularly aware of the potential for damage to penetrating objects
such as vent pipes during the construction process. The perimeter area,
where the drainage layer intersects surface drainage, should be closely
inspected for adherence to the design specifications. More information on
CQA inspection activities for filter layer placement is found in Section
2.3.6.2.4.
2,3.7.2.7 Topsail layer placement—The topsoil layer is the uppermost
component of the cover system. Its functions are to protect the underlying
layers from mechanical and frost damage, and (in conjunction with a vegeta-
tive cover) to protect against erosion.
Topsoil specifications are likely to include properties (e.g., nutrient
and organic content) not required for the other soil components of the
facility. Soil specifications typical of the other earthwork components
may also be included, however.
Reconstruction inspection activities will include checking topsoil
properties against the design specifications and ensuring that deleterious
materials are not included. The foundation for the topsoil layer will be
the filter layer above the drainage layer. The filter layer should be
checked to ensure that it has been constructed to meet or exceed the speci-
fied design and that any specified penetrations are intact and properly
oriented.
During construction of the topsoil layer, CQA inspection personnel
should monitor the uniformity of the application process, observe the
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placement procedure to ensure that the soil is not overly compacted, and
measure the thickness and slope of the topsoil layer. CQA inspection
personnel should also ensure that care is taken in the vicinity of vents or
other protrusions to prevent damage by construction equipment.
In arid areas of the country, where establishment of vegetation is
difficult, erosion protection may be achieved through the use of coarse
material (e.g., cobbles, riprap). When these materials are used, the
inspection should verify that particle size and placement methodology are
as specified in the design.
2.3.7.2.8 Top so i1 s eed i ng--Topsoil placement, preparation for seeding,
and the seeding may take place in a more or less continuous operation.
Inspection before the seeding process should include confirmation that the
soil additives and seed are as specified in the design. Tilling depth
should be measured, and the application rate of additives should be monitored
to confirm that it is as specified in the design. The slope of the final
surface of the cover should also be verified to ensure that it meets the
design requirement. CQA inspection personnel should verify that all vents
and standpipes or any other penetrations through the cover are not damaged
by the tilling and additive application processes.
The seeding method also may be specified in the design, and CQA inspec-
tion personnel should ensure that the application equipment is appropriate
for the job; e.g., if hydromulching is called for, then hydromulching
equipment should be available and used. The rate of seed and mulch appli-
cation, amount and uniformity of coverage, and watering instructions when
specified, should be followed carefully. Perimeter areas should be examined
to ensure that bare spots are not left inadvertently. If tacked mulch is
used, the operation should be observed to ensure that it is as specified.
Timing of seeding is important, particularly for grasses. CQA inspec-
tion personnel should ensure that it occurs during the designated period
and that the weather is favorable. For example, seeding should not take
place during high wind or rain or when the soil is frozen. Description of
the inspection activities that should be conducted during final cover
system seeding may be found in Gilmara et al. (1983).
2.3.7.3 Postconstruction--
CQA inspection personnel should make a visual check of the completed
cover to ensure that it meets the specified design. Slopes should be
surveyed, any unusual depressions should be noted and corrected, and the
vents and standpipes should be examined for alignment and orientation. The
perimeter configuration, including drainage conduits also should be examined
for conformance to design specifications.
Inspection of the cover should continue until it is ascertained that a
vegetation cover has, in fact, been reasonably well established. Grass and
ground cover should be evaluated once a month by a qualified specialist
during the first 4 to 6 months following germination (Gilmaro et al., 1983).
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At that time a final check should be made of the final cover to ensure that
it is as specified.
2.4 SAMPLING STRATEGIES
For many materials and construction processes, it is necessary to
estimate the quality of the overall material or process from the observed
or measured quality of a representative sample that is a small fraction of
the total material or process. Examples of these situations include assess-
ment of characteristics of a soil liner (e.g., permeability, moisture
content, density, particle size distribution) and destructive testing of
FML seams. This section presents information that may be useful in the
selection and implementation of an appropriate sampling strategy for evaluat-
ing construction quality. It is intended to give the reader an introduction
to the concepts and assumptions behind different sampling strategies. It
is not intended to be a complete or comprehensive treatment, of the subject.
Some of the key characteristics and terms of commonly used sampling
strategies that are addressed by this document include:
Data type. Attribute data [such as dichotomous classifications
(defective or acceptable)] are the primary information recorded
for sampling units when the major concern is the percentage (or
number) of sample units that are defective (i.e., exceed or are
less than some prespecified level). Measurement data are collected
when the goal is to compute summary statistics (e.g., means,
variances, ranges). Selection of the type of sampling strategy
(attribute or measurement) is a design function.
Acceptance/ReJection Criten'a. When percentage unacceptable is
the statistic of concern, acceptance/rejection criteria are based
on the maximum percentage of unacceptable units (or measurements)
that can be tolerated. When summary measurements are of concern,
these criteria are based on the nominal level (e.g., mean, variance)
that is considered satisfactory for a specified measurement (e.g,
soil permeability, moisture content). Selection of the appropriate
acceptance (or conversely rejection) criteria is a design function.
Sampling Units (orBlocks). Sampling units or blocks are definite
isolated quantities of material or construction work, constant in
composition and produced by a uniform process, that are eligible
for selection into a sample. Each unit may contain one or more
element that can be further selected for measurement (Section
2.4.1).
Number of Sampling Units and Number of Measurements per Unit.
These numbers may be selected on the basis of judgment or deter-
mined by statistical methods (Sections 2.4.2.2 and 2.4.2.3).
Location(s) of Sampling Units and/or Measurements Within Units.
Locations for individual sampling units and/or measurements may
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be selected on the basis of .judgment or on a random basis (Sections
2.4.2.1 and 2.4.2.2).
Treatme nt of 0u11iers. Criteria for identifying and rejecting
measurements that may be in error, or atypical, may be based on
judgment or on statistical methods (Section 2.4.4).
Corrective Measures. When a sample fails to satisfy the acceptance
criteria or a measurement is identified as an outlier by the
prespecified criteria, some corrective action must be taken
(Section 2.4.5). The actual physical means of correction should
be specified by the designer.
The reader should note that not all of these features apply to all sampling
strategies.
The current state of knowledge on sampling strategies for hazardous
waste land disposal facility CQA is not well-developed enough to enable EPA
to recommend a specific approach for designing a sampling strategy. For
instance, the measurement error inherent in test methods is an important
piece of information when devising a statistical sampling strategy. However,
the measurement error associated with certain important test methods (e.g.,
laboratory and field permeability) is not known. Until more information is
available, the selection of appropriate sampling strategies should be
conducted with the guidance of knowledgeable engineers and statisticians.
2.4.1 Sampling Units and Sample Elements
The term "sampling unit" or "block," as used herein, refers to a
definite, isolated quantity of material, such as soil, of constant composi-
tion and produced by essentially the same process, that is presented for
inspection, acceptance, and/or measurement. Alternatively, it may be a
unit of construction work that is assumed to have been produced by a uniform
process. Examples of sample units or blocks might include a portion of a
lift of compacted fill, a length of membrane seam, or a section of an
exposed face of trench wall. It is characteristic of a block that all
variation among measured properties within it is assumed to be random, with
no underlying differences between locations in the block. The block may be
characterized by a block mean and variance or as acceptable or unacceptable
for each measured characteristic.
Block size is established on the basis of judgment of uniformity of
materials and construction and on economics of inspection. Generally,
materials and construction close together in time or space will be more
similar than those far apart. This may be a single day's production, a
portion of a day's work, a stockpile of material from a uniform, well-defined
source, or a single shipment of offsite material.
For measurement purposes, a sampling unit or block is usually subdivided
into a number of sample units or batches, each a small and easily identified
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unit of length, area, volume, weight, package, or time period. A sample
element is that portion of material removed (or tested in place) from each
selected sample unit or batch. A sample is a collection of sample elements,
such as test bores, truck loads, grid sections, or sections of an FML seam.
Each element in the sample is independent from the other elements in the
sample, and data are collected for each sample element. The sample may
represent a block of construction material or process such as an incoming
shipment of offsite material for the purpose of inspection as a basis for
judging, or estimating, the quality of the block.
2.4.2 Types of Sampling Strategies
The establishment of sampling methods and of sampling and testing
frequency may be based on either judgment or on probabilistic methods using
statistical theory (Deming, 1950). Willenbrock (1976) states that, up
until the last 10 to 15 years "... quality of construction was largely
accomplished through semi-artisan techniques and procedures with constant
visual inspection," or in other words, judgmental sampling. Judgmental
methods are subject to biases and sampling errors (Deming, 1950) dependent
on the knowledge, capability, and experience of the specification writers,
the CQA inspection personnel, and the CQA officer. These factors cannot be
easily evaluated and documented. Methods using statistical theory are more
rational, calculable, and documentable than judgmental methods and are
recommended where feasible and applicable. Whether judgmental or statistical
sampling is to be used, it is imperative that the procedure used is specified
clearly and completely in the CQA plan and is an accepted approach to
sampling the construction materials or operations being evaluated. The
rationale used to select and develop the sampling approach should be explained
in the CQA plan,
2.4.2.1 100-Percent Inspection—
The ideal situation is that where the quality of all of the material
used for a particular component of a hazardous waste land disposal facility
can be assessed by an objective observation or test procedure. Clearly,
these procedures are limited to observations and nondestructive tests that
are relatively inexpensive in terms of resource and time requirements.
Examples of such methods are those tests used for FML seams and anchors,
collection system pipe joints, pump function, electrical connections, and
final leak detection (filling a facility with water). A less than optimum,
but necessary, situation is where the quality of a material is assessed by
subjective evaluation (usually visual inspection) of all of the material.
2.4.2.2 Judgmental Sampling-
Judgmental sampling refers to any sampling strategy where decisions
concerning sample size, selection scheme, and/or locations are based on
other than probabilistic considerations. The objective may be to select
typical sample elements to represent a whole process or to identify zones
of suspected poor quality. Sampling frequency is often specified by the
designer and may be a function of the confidence he has in the CQA personnel.
Selection of the sampling location(s) 1s often left up to CQA inspection
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personnel or the CQA officer making the entire process dependent on the
validity of his judgment.
Two considerations need to be addressed during the selection of sampling
locations by judgment. First, CQA personnel must select sample locations
that they feel are representative of the quality of the work as a whole so
that the inspection results will reflect accurately the as-built conditions.
In addition, they must locate samples in regions of questionable construction
quality to identify work that does not meet design specifications.
There can be no standardized rules for judgmental sampling simply
because such sampling depends on the judgment of the designer, CQA officer,
and/or CQA inspection personnel. Because judgmental sampling strategies
are based on the experience and opinions of the CQA personnel, sample
estimates (e.g., mean, variance, or relationship among variables) may be
biased and hence may not represent accurately the overall material or
process. There is no practical way to test for or to quantify these inherent
biases nor to estimate the level of confidence associated with the sample
estimates. For example, with a judgmental sampling scheme, it is not
possible to estimate how closely the quality measurement of the sample
approximates that of the overall material or process,
2.4.2.3 Statistical Sampling—
There is an inherent, or natural, variability in measurement data for
any specified quality characteristic of most materials and components used
in construction (Terzaghi and Peck, 1967), including the materials and
processes used to construct a hazardous waste land disposal facility. This
variability may be attributed to variability in material quality, construc-
tion operations, measurement techniques and instrumentation, as well as the
overall capabilities of the CQA personnel.
Statistical sampling methods are based on the principles of probability
theory and are used to estimate selected characteristics (e.g., mean,
variance, percent defective) of the overall material or process (popula-
tion). The primary differences between these methods and those based on
judgment are that sample selection is by an objective random process that
reduces the likelihood of selection bias (i.e., every sampling unit has a
known likelihood of selection) and provides a means of assessing the magni-
tude of potential error in the sample estimate(s) (i.e., variability in
sample group estimates that would be observed if multiple groups of indepen-
dent sample elements were selected or the likelihood that the sample estimate
does not deviate from the overall characteristic to be estimated by more
than some specified amount). However, it should be realized that there is
a need for experienced judgment in the selection of appropriate statistical
techniques and in the evaluation of data generated by these techniques.
In statistical sampling, a sample unit refers to entities that are
enumerated for purposes of sample selection and may or may not be the items
that are measured. For example, if a grid is overlaid on a soil liner and
grid sections are selected into the sample, the grid sections are the
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sample units; a single measurement, such as size, might be performed for
each grid section or a sample of smaller units (e.g., core sections) might
be selected from each grid section for testing. The underlying requirement
for a statistical (or random) sample is that all of the units selected into
the sample must have a known probability (chance) of selection into the
sample. An example of a common approach is to assign a unique serial
number to each potential sampling unit in the overall material or process
and select serial numbers by some random process such as drawing numbers
from a hat or using a random number table.
There are many variations in random sampling strategies that can be
used. Some examples are:
If the soil to be used to line a hazardous waste land disposal
facility is known to vary across the borrow source, independent
samples might be selected from each area and the results
combined by a weighting scheme depending on some property of
the differentiating characteristic such as particle size,
consistency, or overall density (stratified sampling).
If it is impractical to enumerate all possible sample items
(or points), it may be possible to select a small number of
large sample units and then select a sample of measurable
elements from each unit. The previously mentioned example
of selecting core sections from a sample of grid sections of
a soil liner illustrates this type of sampling (two-stage
sampling strategy).
If many loads of soil are being hauled to a site and it is
reasonable to assume that the loads are homogeneous relative
to a particular characteristic, it may be desirable to
examine every nth load after starting with a randomly selec-
ted start less than 'n' (systematic sampling).
If the goal is to assess some characteristic of a compacted
soil lift, it may be desirable to overlay the site with a
grid pattern and to select grid sections for sampling by
randomly selecting coordinates. In this situation, if each
section has an equal chance of selection, the plan would be
classified as simple random sampling. If instead the plan
specified that the selection probabilities be in proportion
to some known characteristic such as area of grid section,
it would be classified as a proportionate sampling. For
example, if some grid sections are twice as large as others,
the large sections could be given twice the probability of
selection as the small sections. This will ensure that the
probability of selection per unit area is the same for all
grids and is equivalent to the situation in which all grids
are equal and have an equal probability of being selected.
The primary caution is that selection probabilities be known
in advance or be equal for all units in an area and that an
accepted statistical technique be used for selection of
random numbers.
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The plan used for each evaluation should be tailored to the particular
situation and types of sample estimates desired. If the goal is to estimate
some characteristic of a completed component or process, a simple random
sample design or some modification such as a stratified or two-stage sam-
pling plan should be used. If the goal is to monitor an ongoing operation
such as placement of soils by trucks, a systematic sampling strategy may be
used, where every nth truck would be examined after a random start. The
reason for this selection is that the latter design does not require complete
enumeration of the potential sampling units whereas some such enumeration
scheme is usually necessary for the other designs. Once the data have been
collected from a particular sampling strategy, they must be summarized,
analyzed, and presented in a way that is tailored to the sample design that
was used.
All statistical sampling designs are based on the principles of simple
random sampling. For more information concerning the available sampling
designs or their underlying probability and distributional properties and
assumptions, see Kish (1967).
2.4.3 Selection of Sample Size
The sample size is the number of sample items whose test outcomes are
combined mathematically to estimate population parameters (characteristics
of the overall site or process). Sample size may be selected by judgmental
or statistical methods. The judgmental method is subjective, based on
intuition. Classical statistical methods are based on sample-derived
statistics and on judgment-selected confidence levels.
2.4.3.1 Judgmental Method—
The judgmental method depends almost entirely on the intuition of the
specifier, presumably based on engineering and materials evaluation experi-
ence. All of the comments made earlier, in Section 2.4.2, regarding sampling
methods also apply to sample size selection. Judgmental methods result in
sample means, sample variances, and variable relationships that may be
biased and, therefore, may not accurately represent the overall material or
processes. These biases cannot be quantified; thus, the level of confidence
associated with sample estimates cannot be estimated for judgmental sampling
schemes.
Testing frequency for judgmental sampling schemes is often set to pro-
duce a fixed proportion of the population (such as 10 percent) or to yield
a prespecified sample size per specified unit of time, distance, area, or
volume (e.g., taking samples of FML seams on a per linear foot basis). The
sample proportions or sizes are usually established on the basis of judgment
and experience from similar construction projects. Sampling schemes are
usually used to specify minimum sampling frequencies. These frequencies
can be increased to identify potential problem areas where additional tests
should be made. Samples ideally should be located where CQA inspection
personnel have reason to doubt the quality of materials or workmanship.
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Organizations that construct large numbers of similar projects, such
as the U.S. Army Corps of Engineers or the U.S. Bureau of Reclamation,
often employ judgmental sampling with sampling frequencies based on knowledge
from their years of construction experience. Usually a range of sampling
frequencies is suggested, with estimates of site- and material-specific
variability determining which end of the range to use initially. More
intensive sampling may be specified in areas where design specifications
are difficult to meet, such as in corners of a landfill or equipment turn-
around areas.
Examples of sampling strategies can be found in standard specifications,
such as AASHTO (1983) and ASTM (1985b)5 particularly for sampling and
testing of materials. The sampling of a batch, such as a soil stockpile,
in which some segregation may have naturally occurred, often involves
taking three or more sample items that are blended into a single represen-
tative element for analysis,
2.4.3.2 Statistical Methods—
2.4.3.2.1 Simp1e random sampj ing—A statistically rational and valid
method for selecting sample size is given in ASTM (1985b) E 122-72. The
equation for the number of sample units (sample size, n) to include in a
sample in order to estimate, with a prescribed precision, the average of
some characteristic of a block is:
n = (ts/E)2 (2.1)
or, in terms of coefficient of variation
n = (tV/e)2 (2.2)
where
n = number of units in the sample
t = probability factor
s = the known or estimated true value of the standard deviation for
the overall material or process to be estimated
E = the maximum allowable difference between the estimate to be made
from the sample and the result of measuring (by the same methods)
all of the units in the overall material or process
e = E/X, the allowable sampling difference expressed as a percent (or
fraction) of X
X = the expected (mean) value of the characteristic being measured
V = coefficient of variation.
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The probability factor, t, in equations (2.1) and (2.2) is the standard
normal deviate (see ASTM, 1985b, for description) that corresponds to the
chosen level of confidence that the sample estimate win not differ from
the true value of the "to be estimated" characteristic for the overall
material or process by more than the allowable difference (E). For a
two-sided test (test for error both above and below the estimated value),
the commonly used values of t are 1.96 and 1.64, corresponding to 95 and
90 percent levels of confidence, respectively. For sample sizes less than
thirty, the correct t value can be determined iteratively. For a one-sided
test (test for error in one direction only), a value of 1.64 corresponding
to the 95 percent level is commonly used. For values of t (or z, as indicated
in many tables and texts) corresponding to other levels of confidence, see
any basic statistics book.
As described in ASTM (1985b) E 122-72, the estimated standard deviation,
s, should be derived from previous measurements of standard deviation for
the same material or process, and should have been developed from at least
30 measurements. As new data are collected from subunits of the overall
material or process, they can be used to supplement or replace the old data
(depending on comparability of the new and old data) to further refine the
estimate of s and the resulting sample size estimate. If no previous data
exist, s can be roughly approximated from background knowledge of the shape
of the distribution or by conducting a pilot, or preliminary, study where a
small number of measurements are performed on a subset of the overall
material or process (possibly on the test fills).
It should be recognized that a sample size determination is an esti-
mate (or best guess) of the minimum quantity sufficient to satisfy stated
objectives. Because the estimates are based on historical data or subjective
opinions of the underlying distribution and cannot take into account all of
the factors that contribute to sample variability, they may not be adequate
to produce assessments with the prespecified level of confidence. It is
always necessary to recompute confidence levels as part of the ordinary
data analysis of the sample data. If the resultant confidence level is not
sufficient, it may be necessary or at least desirable to supplement the
sample to attain the desired level. As long as the original sample was
selected by an accepted random process, the test methods have not changed
since the initial sample analysis, and the same sampling scheme used for
the original sample is used for the supplement (i.e., every sample unit has
an equal likelihood of inclusion in either the original or supplemental
samples), it usually will be satisfactory to combine the two samples to
reduce variability of the sample estimates and hence increase the confidence
level. It should be stressed that the purpose of sample supplementation is
to improve estimation precision (i.e., variance of estimates) and not to
change point (mean) estimates; usually the effects of supplementation also
will result in changed point estimates,
A sample size designed to produce estimates with prespecified reliability
or confidence for the overall material or process probably will not be
adequate to assess the quality of some subsection where there is a need for
separate evaluation. For example, the sample size selected for determining
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whether the overall clay liner meets the maximum criteria for permeability
probably will not be sufficient to assess the permeability of a particular
section of the liner where the soil appears to differ from that used in the
rest of liner. Therefore, it may be necessary to increase the sample fre-
quency or sample size for a subarea where visual observations of materials
or construction operations indicate that the quality of construction is
suspect. If these data are to be combined with the rest of the data from
the overall site, all data analyses must include an adjustment for the
differences in sample selection probabilities between the original and
supplemental samples.
2.4.3.2.2 Acceptance saropJJng--Acceptance sampling is the use of a
sample to decide whether a particular section or component of a material or
process meets the specified design. The following example assumes that
acceptance will be based on measurement results, such as soil permeability.
If acceptance is based on attribute data (i.e., each sample element is
classified as defective or acceptable), please refer to standard quality
control references such as Burr (1976).
The following example illustrates one approach for determining if a
clay liner for a proposed hazardous waste land disposal facility satisfies
the specified design permeability of at least 10 8 cra/s or less. It demon-
strates methods for estimating sample size and for developing the sample
evaluation scheme to ensure with prescribed probabilities that a process or
material meets specifications. The assumptions underlying this approach
and example follow. For additional details see Burr (1976).
The standard deviation of permeability measurements is unknown
and will be estimated from the sample data.
The probability distribution of permeability measurements is
normal.
The acceptance quality limit (p^ is 0.2 percent, i.e., it is
acceptable to have 0.2 percent of the samples with permeability
exceeding the criteria of 1 x 10 8 cm/s.
The unacceptable quality limit (p2) is 2 percent, i.e., it is
unacceptable to have 2 percent or more of the samples with permea-
bility exceeding 1 x 1Q 8 cm/s.
The probability of rejecting the liner as unacceptable (based on
the sample) when it is indeed acceptable (0.2 percent or less of
all potential soil samples from the total liner have permeability
exceeding 1 x 1Q~8 cm/s) should not exceed 0.10.
The probability of accepting the liner (based on the sample
results) when it is not acceptable (2 percent or more of all
potential soil samples from the total liner have permeability
exceeding 1 x IQ 8 cm/s) should not exceed 0.01.
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Based on these assumptions, the required sample size is determined as
follows:
n = (q2 + 2) / 2 x t(za + zb) / (zpl - zp2)F
= sample size
where
z = standard normal deviate corresponding to the one tailed probability
a of rejecting an acceptable liner, (z = 1.282 corresponding
to 0.10 in the example.)
z, = standard normal deviate corresponding to the one tailed probability
of accepting an unacceptable liner, (z. = 2.326 corresponding
to 0.01 in the example.)
z , = standard normal deviate corresponding to the one tailed acceptable
p proportion (probability) of failures, (z , = 2.88 correspond-
ing to 0.002 in the example.) p
z 2 = standard normal deviate corresponding to the one tailed unacceptable
proportion (probability) of failures, (z , = 2.055 correspond-
ing to 0.02 in the example.) "
^ = (2a x Zp2 * 2b X zpl> / (za + zb}
(q = 2.5869 in the example)
Hence, the required sample size is:
n = [(2.5S692 + 2) / 2] x [(1.282 + 2.326) / (2.88 - 2.055)]2
= 83.1216 or 84 sampling units.
The plan, or strategy, is to select a sample of 84 soil sample elements
and to measure the permeability of each. Compute the mean "avg" and standard
deviation "s" of these measurements. Acceptance or rejection of the liner
should be based on the following criteria:
avg + q x s < U accept
avg + q x s > U reject
where
U = acceptable permeability value (1 x 10 8 cra/s).
Hence, if the mean and standard deviation of the 84 permeability measurements
are 1 x 10 9 cm/s and 1.4 * io~8 cm/s, the liner would be accepted because
1 x 10"9 cm/s + 2.5869 x 1.4 x 10~9 cm/s = 3.62 x lo"9 cm/s <1 x 1Q~8 cm/s.
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For other situations, such as when there is a lower specification
limit, there are both upper and lower specification limits, and/or there is
a reasonable basis for assuming that the measurement variance is known
prior to sampling. If so, consult standard statistical quality control
texts such as Burr (1976).
2.4.3.2.3 Sequential sampling—All of the sampling strategies and
sample size estimates discussed so far (with the possible exception of
sample supplementation to reduce variance of sample estimates) assume that
the sample size or sampling frequency will be determined prior to initiation
of the sampling program (i.e., the data from the sample will not influence
these estimates). A sequential sampling strategy does not initially set
sampling size or frequency; instead, after each sample element is inspected,
a decision is made to accept the block it represents, to reject it, or to
inspect another element (i.e., there is not sufficient data to evaluate the
quality of the block). If the quality of the inspected block is very good
or very bad, only a minimum number of sample elements will need to be
tested to accept or reject the block. If the block is marginal in its
quality (i.e., close to the acceptance/rejection criteria), the sequential
sampling strategy will require more tests, up to the number required by a
fixed sampling strategy. Sequential sampling strategies generally require
fewer sampling units to obtain sufficient data for the evaluation of quality
than do single sampling strategies and therefore can offer some advantages
in terms of cost and time requirements.
The general approach to sequential sampling is to determine after
selection and testing of. each sample unit if an evaluation can be performed
with acceptable precision. If so, the sampling process is terminated; if
not, another sample unit is selected. Hence, if the test results are very
uniform and at the levels originally hypothesized (or desired) or if the
results deviate markedly from the hypothesized (or desired) levels, a
decision to accept or reject the material or process can be made with few
sample units. If, however, the data are highly variable and reasonably
close to the rejection criteria, a larger sample will be required before a
decision can be made. Hence, the sample size is a variable in this type of
sampling design. For more information on sequential sampling, the reader
is referred to Burr (1976).
2.4.3.2.4 Assessment of sources of variability—The previous discussion
on statistical sampling strategies has not considered the fact that varia-
bility in test results can result from errors associated with the testing
procedure and thus may not reflect the true variability of the parameter
being measured. To apply a statistical sampling strategy, it is important
to determine the sources of variability present in the measurement of the
parameter in question. This requires determination of the precision and
accuracy of the test methods used for measurement and consideration of
these factors in the analysis of data variability.
Unfortunately, precision and accuracy of many of the test methods that
are critical to evaluating the construction quality of a hazardous waste
land disposal facility (e.g., field and laboratory permeability of a soil
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liner} are not presently known. This necessitates estimation of these
parameters if statistical sampling strategies are to be properly applied.
This estimation may be done by judgment if the engineer designing the
sampling strategy is very familiar with the test method in question, but it
is better to base these estimates on replicate measurements of batches of
the material in question that are known to be uniform with respect to the
properties being measured. A replicate measurement is defined as one in
which every conceivable factor that could influence measurement results is
the same as in the original test. Test replication can be used to determine
repeatability, or single operator precision.
If multiple operators will be conducting a test, or if other factors
influencing test results (e.g., weather conditions) are likely to vary
during the course of testing, test reproducibility also should be assessed.
Test reproducibility can be assessed by retaining an area or volume of the
tested material, which is uniform in its properties, for the duration of
construction. This material may be sampled and tested regularly throughout
construction to determine if measurement techniques have changed. In
addition, if a change in testing conditions occurs that could have an
effect on test results (e.g., a different test operator or a change in
weather conditions), the effect of this change may be assessed by conducting
tests on the retained material.
2.4.4 Treatment of Outliers
Occasionally, in a supposedly homogeneous sample, one of the test
values appears to deviate markedly from the remainder of the sample. Such
a value is called an outlier. Rules for rejection of outliers are based on
confidence level criteria. Standard practice for dealing with outlying
observations is contained in ASTM (1985b) E 178. This practice may be
applied only to random, statistically evaluated samples. According to
ASTM E178, two alternative explanations for outliers are of interest:
An outlying observation may be an extreme manifestation of
the random variability inherent in the data. In this case,
the value should be retained and processed with the other
observations in the sample.
An outlying observation may result from gross deviation from
the test procedure or an error in calculating or recording
the numerical value. In this case, the outlier may or may
not be rejected. If used in the subsequent analyses, the
outlying values may be recognized as being from a different
population than the other sample values.
ASTM E178 provides statistical rules that lead the investigator to look for
causes of outliers and decide which of the above alternatives apply so that
the most appropriate action may be taken in further data analysis. The
procedures used are too extensive to quote in this document, and the reader
is referred to ASTM (1985b). For more information concerning available
specialized tests for outliers and the assumptions underlying these tests,
see Barnett and Lewis (1978) or Dixon and Massey (1957).
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2.4,5 Corrective Measures
When material or work is rejected because observations or tests indicate
that it does not meet the design specifications, corrective measures must
be implemented. For material subject to 100-percent inspection, substandard
material is simply rejected. When workmanship subject to 100-percent
inspection is rejected (e.g., synthetic membrane seams), it must be redone
until it meets specifications. For material or workmanship subject to
judgmental or statistical methods, in question because of CQA inspection
personnel observations or test results, additional testing of the component
may be necessary prior to rejecting the block of work and specifying correc-
tive measures. This additional testing can help determine the cause of the
problem so that it may be avoided in the future. It also will define the
extent of the problem so that adequate corrective measures can be specified.
For any facility component, the actual physical means of corrective
measures, in the case of noncompliance, is a combined design and construc-
tion function. Both of the latter topics are beyond the scope of this
document. Regardless of the means of correcting the deficiency, CQA personnel
should inspect the correction to ensure that the specified design has been
met.
2.4.6 Control Charts
For some materials or processes it may be desirable to maintain records
of quality over time. For example, it may be necessary to assess the
particle size of truck loads of incoming soils used in preparing the liner.
Assuming that the loads are relatively homogeneous (there are no major
differences in soil types or moisture content among the loads), a control
chart approach might be used. A systematic sampling strategy could be used
to select incoming truck loads for analysis, and the test results would be
plotted against time. These types of plots provide a means to keep track
of the incoming materials so that appropriate action may be taken whenever
it is indicated (actions to be taken in response to deviations from the
norm should be specified by the design engineer). For some material or
properties, deviations in quality in either direction may be important
(such as soil moisture content); for others, deviations in only one direction
will be of concern (such as soil permeability).
One of the fundamental questions of this approach is: What is an
abnormal test result? Upper and lower limits of acceptability about the
norm or mean of the test results can be established by assuming that the
measurements are normally distributed and setting limits that will include
a predetermined proportion of the measurements (usually 90 or 95 percent)
or by setting_them at some predetermined level of acceptability (such as a
maximum of 10 8 level of permeability for soils used as liner material).
For those measurements where little is known concerning natural variability
and there is no sound basis for setting a level of acceptability, the test
results from experimental sites (e.g., test fills) could be used to estab-
lish a norm and usual variation that could be used for setting up the
control chart.
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It will likely be advisable to revise the control chart limits as
tests are performed on the disposal site; these changes should only be done
with the concurrence of the CQA officer and the design engineer. All
measurements that fall outside the established limits should be referred to
the CQA officer, who will attempt to identify the cause for deviation and
the appropriate action to rectify the problem; specific responses to devia-
tion should be specified by the design engineer. The usual practice in
quality control statistics is to record summary results (means, standard
deviations, or ranges) of multiple measurements for each sample, where each
sample consists of a series of sample elements; an example of this approach
might be used in a design where large soil samples are selected from a
liner by a grid system and multiple measurements of soil density are performed
for each grid section. For land disposal sites, however, it will probably
be more common to record individual measurements on the control chart
(Burr, 1976). The sample size/frequency (number of sample unit or sampling
interval), sampling unit (e.g., truck load, grid section of liner), and
acceptance criteria must be determined by the design engineer and will
depend on the specific goal of an assessment, the site-specific character-
istics of a particular material or process to be evaluated, and the expected
variability of the test data.
Control charts can be used to monitor the quality of material or
constructed work over time, providing a useful record of material variability
or of.the performance of a construction contractor as the facility is con-
structed. For example, the owner/operator, design engineer, construction
contractor, or CQA officer may use these charts to detect trends in workman-
ship quality that may not be apparent when comparing the results of individual
tests. With the use of control charts, declines in workmanship quality can
be correlated with potential causes (e.g., weather conditions), and appropriate
corrective measures (e.g., changes in operating procedures, additional
training programs, or more frequent testing) may be implemented in a timely
"fashion. Another example would be using control charts to detect increases
in material variability that may require more frequent testing of the
incoming material.
Properly maintained control charts can provide an immediate review of
the quality of a block of material or workmanship (Beaton, 1968). They
provide a convenient and concise means of documenting construction quality
and may serve to summarize a great volume of test reports and other records,
speeding up review of test records and acceptance of a block of completed
work.
An example of a control chart is presented in Figure 2-3. In the
upper graph, individual test results for a block of material are plotted in
chronological order. In the lower graph, a moving average of the test
results is plotted on a graph. If the average test results are in the
shaded area (approaching the rejection level), more frequent testing is
required to accept the lot. Below the shaded area, the lot is accepted;
above it, it is rejected. If statistical sampling methods are used, the
acceptance/rejection levels and the levels requiring more testing may be
determined by statistical methods, as described earlier in this section.
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Test More Frequently
12
13
14 15
Moving Averap
16
18
(Beaton, 1968)
Figure 2-3. Control charts: individual and moving average.
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Kotzias and Stamatopoulos (1975) used three types of control charts
with judgmental sampling methods to evaluate construction quality for an
earthen dam. Simple quality control charts were used to evaluate day-to-day
construction performance. These charts plotted daily averages and ranges
of test results over the course of the construction period and are valuable
chronological records, but are not formal control charts. Rejection charts
(Figure 2-4) cumulatively plot the total number of rejected tests and the
magnitude of each rejected result against the total number of test results
(retests excluded). These charts reveal the rejection rate and the severity
of defects in the rejected material (compacted earthfill). Finally, fre-
quency diagrams (Figure 2-5) were plotted for whole components or for
sampling blocks. These diagrams were presented in pairs, i.e., defects
included, retests excluded (before remedial action), and defects excluded,
retests included (as accepted). These charts are bar diagrams plotting
number of test results against test results (Figure 2-5). Evaluated jointly
with rejection charts (Figure 2-4), they provide a way of determining the
overall importance of defects and remedial measures.
Although control charts may be used with either judgmental or statistical
sampling, when used with judgmental methods they reflect the bias inherent
in the judgmental sampling. Thus, the "as accepted" frequency diagrams may
not accurately represent the quality of the completed work when used with
judgmental sampling, but they will for a sampling strategy determined by
statistical methods.
For more information concerning the use of control charts, see standard
texts concerning quality control such as Duncan (1959), Burr (1976), or
Grant (1964).
2.5 DOCUMENTATION
The ultimate value of a CQA plan depends to a large extent on recogni-
tion of all of the construction activities that should be inspected and the
assignment of responsibilities to CQA inspection personnel for the inspection
of each activity. This is accomplished most effectively by documenting CQA
activities and should be addressed as the fifth element of the CQA plan.
The CQA personnel will be reminded of the items to be inspected, and will
note, through required descriptive remarks, data sheets, and checklists
signed by them, that the inspection activities have been accomplished.
2-5-l Daily Recordkeeping
Standard daily reporting procedures should include preparation of a
summary report with supporting inspection data sheets and, when appropriate,
problem identification and corrective measures reports.
2.5.1.1 Daily Summary Report—
A summary report should be prepared daily by the CQA officer. This
report provides the chronologic framework for identifying and recording all
other reports. At a minimum, the summary reports should include the following
information (Spigolon and Kelley, 1984):
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11
IS
Is
if
IS
"I
H3
a> UJ
Total Number of Test Results (Reteste Excluded!
30 40 SO 60 70 80 90
letat number of lest results:
Total number of rejects: 30
Average rejection rate: 34%
Percent of total volume of dam
30% E.T.C. - percent refection
(Beaton, 1968}
Figure 2-4. Rejection chart: density measurements for dam core compaction control.
70
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REJECTED
ACCEPTED
As accepted
X - 100.55
a =2.00
N =99
Before remedial action
X = 98.50
a =3.76
Before remedial action
90 92 94 96 98 100 102 104
% Compaction
From Kotzias and Stamatopoulos, 197i
Figure 2-5. Frequency diagram: density measurements for dam core compaction control.
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Unique Identifying sheet number for cross-referencing and
document control
Date, project name, location, and other identification
Data on weather conditions
Reports on any meetings held and their results
Unit processes, and locations, of construction under way
during the timeframe of the daily summary report
Equipment and personnel being worked in each unit process,
including subcontractors
Descriptions of areas or units of work (blocks) being inspected
and documented
Description of offsite materials received, including any
quality verification (vendor certification) documentation
Calibrations, or recallbrations, of test equipment, including
actions taken as a result of recalibration
Decisions made regarding approval of units of material or of
work (blocks), and/or corrective actions to be taken in
instances of substandard quality
Unique identifying sheet numbers of inspection data sheets
and/or problem reporting and corrective measures reports
used to substantiate the decisions described in the preceding
item
Signature of the CQA officer.
Items above may be formulated into site-specific checklists and data
sheets so that details are not overlooked.
2.5.1.2 Inspection Data Sheets--
All observations, and field and/or laboratory tests, should be recorded
on an inspection data sheet. Required data to be addressed for most of the
standardized test methods are included in the pertinent AASHTO (1983) and
ASTM (1985a) Standards. Examples of field and/or laboratory test data
sheets are given in Department of the Army (1970, 1971) manuals and in
Spigolon and Kelley (1984).
Because of their highly specific nature, no standard format can be
given for data sheets to record observations. Recorded observations may
take the form of notes, charts, sketches, photographs, or any combination
of these. Where possible, a checklist may be useful to ensure that no
pertinent factors of a specific observation are overlooked.
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At a minimum, the inspection data sheets should include the following
information (Spigolon and Kelly, 1984):
Unique identifying sheet number for cross-referencing and
document control
Description or title of the inspection activity
Location of the inspection activity or location from which
the sample increment was obtained
Type of inspection activity; procedure used (reference to
standard method when appropriate)
Recorded observation or test data, with all necessary calcu-
lations
Results of the inspection activity; comparison with specifica-
tion requirements
Personnel involved in the inspection activity
Signature of the appropriate CQA inspection personnel and
concurrence by the CQA officer.
Items above may be formulated into site-specific checklists and data sheets
so that details are not overlooked.
2.5.1.3 Problem Identification and Corrective Measures Reports—
A problem is defined herein as material or workmanship that does not
meet the specified design. Problem Identification and Corrective Measures
Reports should be cross-referenced to specific inspection data sheets where
the problem was identified. At a minimum, they should include the following
information:
Unique identifying sheet number for cross-referencing and
document control
Detailed description of the problem
Location of the problem
Probable cause
How and when the problem was located (reference to inspection
data sheets)
Estimation of how long problem has existed
Suggested corrective measure
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Documentation of correction (reference to inspection data
sheets)
Final results
Suggested methods to prevent similar problems
Signature of the appropriate CQA inspection personnel and
concurrence by the CQA officer.
In some cases, not all of the above information will be available or obtain-
able. However, when available, such efforts to document problems could
help to avoid similar problems in the future.
Upon receiving the CQA officer's written concurrence, copies of the
report should be sent to the design engineer and the facility owner/opera-
tor for their comments and acceptance. These reports should not be submitted
to the permitting agency at that time unless they have been specifically
requested. However, a summary of all data sheets and reports may be required
by the permitting agency upon completion of construction.
2.5.2 Photographic Reporting Data Sheets
Photographic reporting data sheets also may prove useful. Such data
sheets could be cross-referenced or appended to inspection data sheets
and/or problem identification and corrective measures reports. At a minimum,
photographic reporting data sheets should include the following informa-
tion:
A unique identifying number on data sheets and photographs for
cross-referencing and document control
The date, time, and location where the photograph was taken and
weather conditions
The size, scale, and orientation of the subject matter photographed
Location and description of the work
The purpose of the photograph
Signature of the photographer and concurrence of the CQA officer.
These photographs will serve as a pictorial record of work progress,
problems, and corrective measures. They should be kept in a permanent
protective file in the order in which they were taken. The file should
contain color prints; negatives should be stored in order in a separate
file.
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2-5.3 Block Evaluation Reports
Within each inspection block, there may be several quality character-
istics, or parameters, that are specified to be observed or tested, each by
a different observation or test, with the observations and/or tests recorded
on different data sheets. At the completion of each block, these data
sheets should be organized into a block evaluation report. These block
evaluation reports may then be used to summarize all of the site construc-
tion activities.
Block evaluation reports should be prepared by the CQA officer and, at
a minimum, include the following information (Spigolon and Kelley, 1984):
Unique identifying sheet number for cross-referencing and
document control
Description of block (use project coordinate system to
identify areas, and appropriate identifiers for other units
of material or work)
Quality characteristic being evaluated; references to design
criteria, plans, and specifications
Sampling requirements for the inspected block and how they
were established
Sample item locations (describe by project coordinates or by
a location sketch on the reverse of the sheet)
Inspections made (define procedure by name or other identifier;
give unique identifying sheet number for inspection data
sheets)
Summary of inspection results (give block average and, if
available, the standard deviation for each quality charac-
teristic)
Define acceptance criteria (compare block inspection data
with design specification requirements; indicate compliance
or noncompliance; in the event of noncompliance, identify
documentation that gives reasons for acceptance outside of
the specified design)
Signature of the CQA officer.
2-5.4 Acceptance of CompletedComponents
All daily inspection summary reports, inspection data sheets, problem
identification and corrective measures reports, and block evaluation reports
should be reviewed by the CQA officer. The documentation should be evaluated
and analyzed for internal consistency and for consistency with similar work.
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Timely review of these documents will permit errors, inconsistencies, and
other problems to be detected and corrected as they occur, when corrective
measures are easiest.
The above information should be assembled and summarized into periodic
Acceptance Reports. The reports should indicate that the materials and
construction processes comply with the specified design. These reports
should be included in project records, submitted to the facility owner/
operator, and, if requested, submitted to the permitting agency.
2.5.5 Final Documentation
At the completion of the project, the facility owner/operator should
submit a final report to the permitting agency. This report should include
all of the daily inspection summary reports, inspection data sheets, problem
identification and corrective measures reports, block evaluation reports,
photographic reporting data sheets, acceptance reports, deviations from
design and material specifications (with justifying documentation), and
as-built drawings. This document should be certified correct and included
as part of the CQA plan documentation.
2.5.5.1 Responsibility and Authority-
The final documentation should reemphasize that areas of responsibility
and lines of authority were clearly defined, understood, and accepted by
all parties involved in the project. Signatures of the facility owner/
operator, design engineer, CQA officer, and construction contractor should
be included as confirmation that each party understood and accepted the
areas of responsibility and lines of authority and performed their func-
tion(s) in accordance with the CQA plan.
2.5.5.2 Relationship to Permitting Agencies-
Final documentation submitted to the permitting agency as part of the
CQA plan documentation does not sanction the CQA plan as a guarantee of
facility construction and performance. Rather, the primary purpose of the
final documentation is to improve confidence in the constructed facility
through written evidence that the CQA plan was implemented as proposed and
that the construction proceeded in accordance with design criteria, plans,
and specifications.
2.5.6 Document Control
The CQA plan and all CQA documentation should be maintained under a
document control procedure. This indexing procedure should provide for
convenient replacement of pages in the CQA plan, thereby not requiring a
revision to the entire document, should identify the revision status of the
CQA documents, and should enable the CQA documents to be organized in terms
of their relationship to each other, the CQA plan, and the time and location
of the materials and/or workmanship that they represent.
Each page of the CQA plan should have the following indexing information
in the top right corner:
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Section no.
Revision no.
Date (of revision)
Page no. (e.g., 1 of 12) by section.
The table of contents should follow the same structure as the text, including
the above information for each section of the document. This will allow
convenient revision of the document and will help ensure that the most
current revision of the plan is in use.
For CQA documentation, a control scheme should be used to organize and
index all CQA documents. This scheme should be designed to allow easy
access to all CQA documents and should enable a reviewer to identify and
retrieve original data sheets for any completed block of work or facility
component. This will require a unique identifying number for each CQA
record and an indexing scheme to relate summary reports to the original
inspection data sheets. For example, each daily summary report should
clearly identify the inspection data sheets upon which it is based. Problem
identification and corrective measures reports also should identify the
pertinent inspection data sheets that identified the substandard materials
or workmanship, and inspection data sheets that document construction
quality after implementation of the corrective measures. The document
control scheme to be used to organize CQA records for a specific site
should be described in detail in the CQA plan,
2.5,7 Storage of Records
During the construction of a hazardous waste land disposal facility,
the CQA officer should be responsible for all facility CQA documents. This
includes the CQA officer's copy of the design criteria, plans, and specifi-
cations, the CQA plan, and the originals of all the data sheets and reports.
Duplicate records may be kept at another location to avoid loss of this
information if the originals are destroyed.
Once facility construction is complete, the document originals should
be stored by the owner/operator in a manner that will allow for easy access
while still protecting them from any damage. An additional copy should
also be kept at the facility if this is in a different location from the
owner/operator's files. A final copy should be kept by the permitting
agency in a publicly acknowledged repository. All documentation should be
maintained through the operating and postclosure monitoring periods of the
facility.
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REFERENCES (continued)
Kotzias, P. C., and A. C. Stamatopoulos. 1975. Statistical Quality Control
at Kastraki Earth Dam, Journal of the Geotechnical Engineering Division.
ASCE. Vol. 101.
Lanz, L. J. 1968. Dimensional Analysis Comparison of Measurements Obtained
in Clay with Torsional Shear Instruments. Master of Science Thesis,
Mississippi State University, Starkville, MS.
Mitchell, D. H. , and G. E. Spanner. 1984. Field Performance Assessment of
Synthetic Liners for Uranium Tailing Ponds-~A Status Report. Battelle
Pacific Northwest Laboratory. Richland, WA. PNL-50Q5, pp. 31-42.
Morrison, W. R., E. W. Gray, Jr., D. B. Paul, and R. K. Frobel. 1982.
Installation of Flexible Membrane Lining in Mt. Elbert Forebay Reservoir.
REC-ERC-82-2. U.S. Bureau of Reclamation. Denver, CO.
NSF (National Sanitation Foundation). 1983. Standard Number 54 for Flexible
Membrane Liners. Ann Arbor, MI.
Page, A. L. (ed.). 1982. Methods of Soil Analysis, Part 2. Chemical and
Microbiological Properties, 2nd ed. Part 9 in Agronomy. American
Society of Agronomy, Inc. Madison, WI.
Schmidt, Richard K., Ph.D. 1983. Specification and Construction Methods
for Flexible Membrane Liners in Hazardous Waste Containment. Technical
Report No. 102. Bundle Lining Systems, Inc. Houston, TX.
Spigolon, S. J., and M. F. Kelley. 1984. Geotechnical Assurance of Con-
struction of Disposal Facilities. Interagency Agreement No. AD-96-F-
2-A077, Solid and Hazardous Waste Research Division, Municipal Environ-
mental Research Laboratory, U.S. Environmental Protection Agency,
Cincinnati, OH. EPA 600/2-84-040.
Teriaghi, K,, and R. B. Peck. 1967. Soil Mechanics in Engineering Practice.
John Wiley and Sons, Inc. New York.
USBR (U.S. Bureau of Reclamation). 1974, Earth Manual, 2nd ed. Washington,
DC.
U.S. Department of the Array. 1977. Construction Control for Earth and
Rockfill Dams. EM 1110-2-1911. Washington, DC.
U.S. Department of the Army. 1970. Laboratory Soils Testing. EM 1110-2-
1906, W/Chl. Washington, DC.
U.S. Department of the Army. 1971. Materials Testing. TM-5-530. Washing-
ton, DC.
81
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REFERENCES (continued)
VanderVoort, John. 1984, Comprehensive Quality Control in the Geomembrane
Industry Schlegel Lining Technology, Inc. The Woodlands, TX,
Willenbrock, J. H. 1976. A Manual for Statistical Quality Control of
Highway Construction, Vols. 1 and 2. Purchase Order No. 5-1-3356,
Federal Highway Administration. Washington, DC.
82
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APPENDIX A. INSPECTION METHODS USED DURING THE CONSTRUCTION OF HAZARDOUS
WASTE UNO DISPOSAL FACILITIES
Facility component
Factors
to be inspected
Inspection methods
Test ntethod reference
Foundation
Removal of unsuitable
materials
Proof rolling of
subgrade
Filling of fissures or
voids
Compaction of soil
backfill
Observation
Observation
Observation
NA
(See low-permeability
soil liner component)
Surface finishing
Sterilization
Slope
Depth of excavation
Seepage
Soil type (index
properties)
Cohesive soil consist-
ency (field)
Strength (laboratory)
Dikes Dike slopes
Dike dimensions
Compacted soil
Drainage system
Erosion control measures
Observation NA
Supplier's certification NA
and observation
Surveying NA
Surveying NA
Observation NA
Visual-manual procedure ASTM B2488
Particle size analysis . ASTH 0422
Atterberg limits ASTM D4318
Soil classification ASTM D2487
Penetration tests ASTM D3441
Field vane shear test ASTM D2573
•Hand penetroneter Horslev, 1943
Handheld torvane Law, 1968
Field expedient unconfined TM 5-530 (U.S. Dept.
compression of An«y, 1971)
Unconfined cowpressve ASTM 02166
strength
Triaxial compression ASTM 02850
Unconfined compress ive ASTM 01633
strength for sail-cement
Surveying NA
Surveying; observations NA
(See low-permeability
soil liner component)
(See leachate collection systea component)
(Sse cover system component)
For all test Methods, the nost up-to-date standard should be used.
(continued)
83
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APPENDIX A (continued)
Facility component
Factors
to be inspected
Inspection methods
Test method reference
low-p*nMatil1ty
soil liner
Coverage
Thickness
Clod size
Tying together of lifts
Slope
Installation of protec-
tive cover
Soil type (index
properties)
Moisture content
Irrplace density
Hoi sture-dens ity
relations
Strength (laboratory)
Cohesive soil consist-
ency (field)
Permeability
(laboratory)
Observation
Surveying; measurement
Observation
Observation
Surveyi ng
Observation
Visual-manual procedure
Particle size analysis
Atterberg limits
Soil classification
Oven-dry method
Nuclear method
Calcium carbide (speedy)
Frying pan (alcohol or
gas burner)
Nuclear methods
Sand cone
Rubber balloon
Drive cylinder
Standard proctor
Modified proctor
Soil-cement H-D test
Unconfined conpressive
strength
Triaxitl compression
Unconfined conpressive
strength for soil-cement
Penetration tests
Field vane shear test
Hand penetrometer
Handheld tor-vane
Field expedient unconfined
compression
Fixed wall
Flexible mil
NA
NA
NA
NA
NA
ASTM 02488
ASTH D422
ASTM 04318
ASTM 0248?
ASTM 02216
ASTM 03017
AftSHTO T21?
Spigolon & Kelley
(1984)
ASTM 02922
ASTM D1556
ASTM D2167
ASTO D293?
ASTM D698
ASTM D1557
ASTH DS58
ASTH 02166
ASTM 02850
ASTM 01633
ASTM 03441
ASTM 02573
Horslev, 1943
lam, 1968
TM 5-530 (U.S. Oept.
of Army, 1971)
EPA, 1983. SW-870
Daniel et al., 1384
Daniel et al., 1985
SW-846 Method 9100
(EPA, 1984)
Pel-usability
(field)
Large diameter single- ring
infiltroaeter
Sai- Anderson infiltrometer
Day and Daniel, 1385
Anderson et al . , 1984
(continued)
84
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APPENDIX A (continued)
Factors
Facility component to be inspected
Susceptibility to frost
damage
Volume change
Inspection methods
Susceptibility classifi-
cation
Soil -cement freeze-thaw test
Conselidoroeter (undisturbed
or remolded sample)
Soil -cement wet-dry test
Soil -cement freeze-thaw test
Test method
Chamberlin,
ASTM D560
HolU, 1965
ASTM 0559
ASTM D560
reference
1981
Flexible membrane liners
Thickness
Tensile properties
Tear strength
Bonding materials
Bonding equipment
Handling and storage
Thickness of unreinforced ASTM D1S93
plastic sheeting (para-
graph 8.1,3, deadweight
method—specifications for
nonrigid vinyl chloride
plastic sheeting
Thickness of reinforced ASTM 0751
plastic sheeting (testing
coated fabrics)
Tensile properties of ASTM 0638
rigid thick plastic
sheeting (standard method
test for tensile proper-
ties of plastics)
Tensile properties of ASTM 0751
reinforced plastic sheet-
ing {Grab method A--
testing coated fabrics)
Tensile properties of thin ASTM 0882
plastic sheeting
Tear strength of reinforced ASTM 0751
plastic sheeting (nodifled
tongue tear method B--
testing coated fabrics)
Tear strength of plastic ASTM D1004
sheeting (Die C—test
method for initial tear
resistance of plastic film
and sheeting)
Manufacturer's NA
certification
Manufacturer's NA
certification
Observation NA
(continued)
85
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APPENDIX A (continued)
Facility component
Factors
to be inspected
Inspection methods
Test method reference
l*»chate collection system
• Granular drainage and
filter layers
Seami rig
Synthetic drainage and
filter layers
Sealing around penetra-
tions
Anchoring
Coverage
Installation of upper
bedding layer
Thickness
Coverage
Soil type
Density
Permeability
(laboratory)
Material type
Ply adhesion of reinforced ASTM D413
synthetic nenbranes, bonded ASTH 04437
sean strength in peel
(machine method. Type A
ttst methods for rubber
properties, adhesion to
flexible substrate)
Bonded seam strength in ASTH 0751
shear of reinforced plastic
sheeting (modified grab
method A—testing coated
fabrics)
Bonded seam strength in ASTM 03083
shear of unreinforced
plastic sheeting (modified)
Observation NA
Observation NA
Observation MA
Observation NA
Surveying; measurement NA
Observation NA
Visual-manual procedure ASTM D2488
Particle size analysis ASTK 0422
Soil classification ASTM D2487
Nuclear methods ASTM D2922
Sand cone ASTM 01556
Rubber balloon ASTH D2167
Constant head ASTH 02434
Manufacturer's certifies- NA
tion
Handling and storage
Coverage
Observation
Observation
NA
NA
(continued)
86
-------
APPENDIX * (continued}
Factors
Facility component to be Inspected
Overlap
Temporary anchoring
Folds and wrinkles
Geetextile properties
Inspection Methods
Observation
Observation
Observation
Tent He strength
Puncture or bunt
resistance
Tear resistance
Flexibility
Outdoor weatherability
Short-ter* cheatcal
resistance
Fabric per»e«bnity
Percent open area
Test •ethod reference
NA
HA
NA
Norz (198*)
Horz (1984
Hen (1964)
Horz (1984)
Horz (19M)
Horz (1M4)
Horz (1984)
Horz (1984),
Pipes
Material type
Handling and storage
Location
Layout
Orientation of
perforations
Jointing
Manufacturer'§ certifica-
tion
Observation
Surveying
Sumeylno;
Observation
MA
NA
NA
NA
NA
• Solid pressure pipe
• Perforated pipe
* Cait-ln-place concrete Sampling
structures
Consistency
Coapreulve strength
Air content
Unit weight, yield, and
air content
Fora work inspection
Hydrostatic pressure test
Observation
SaapHng fresh concrete
Sluap of Portland caMnt
.concrete
Naklng, curing, and tasting
concrete speciMttt
Pressure Mthod
SravlMtric oetnod
Observation
Section 4,
NA
ASTN cm
ASTM C143
Asmcai
AST* CZ31
ASTM C138
NA
AUWA C60D
-
(continued)
87
-------
APPENDIX A (continued)
Factors
Fecllity component to be inspected
• Electrical and Equipa*nt type
Mchanical equipnent
Material type
Opt ration
Electrical connection!
Insulation
Grounding
Inspection ewtbods
Manufacturer's
certification
Manufacturer's
certification
As per Mmtfacturer's
Instructions
As par Manufacturer's
Instructions
As per manufacturer's
Instructions
As per Manufacturer's
Test ewthod reference
NA
NA
HA
HA
HA
HA
Cover system
• Cover foundation
Haste placement records/
waste placement prociss
Instructions
Observation
NA
• Low-perneabi 1 1 ty
soil barrier
* flexible »e»brane
barrier
* Bedding layer
• Drainage and gas
venting layers
• Tgpso1l and vegetation
(erosion control
•assures)
(See Io*rper»eabil1ty sell liner component)
(See flexible MSMbrane
(See flexible MHbrane
liner component}
liner component)
(Set leachatt col lection systaai eonponent)
Thickness
Slope
Coverage
Nutrient content
Soil pH
Soil type; Moisture
content
Vegetation type
Seeding tlaw
Survey ing
Surveying
Observations
Various procedure!
Salt pH; KM requ1rea«nt
(See lotrperMabfUty sell
Supplier's certification;
observe t low
Supplier's recoeaendations;
observations
NA
NA
NA
fage. 1982
•age, 1982
liner ce«ponent)
NA
MA
*U.S. OOVEIWMENT PRINTING OFFICE : 1966-748-121/40677
88
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